## treydwg 2 years ago 64s^2+144s=-81 can anyone help on this one. Solving for s

64s^2+144s+81=0 (8s+9)^2=0 8s+9=0 8s=-9 s=-9/8

2. treydwg

hmmm?

3. treydwg

@marsss Thank you for the setup

4. godorovg

5. treydwg

i believe it is too

@godorovg you're a genius :)

@treydwg you're too :)

8. treydwg

thanks lol

9. treydwg

so the solution set would be

10. treydwg

I working on it

11. godorovg

in this problem the first clue is being = 0 usally says Quad needs to be used.

12. treydwg

What is the easier way of working out qUADRATIC without using the quad formula?

13. godorovg

64^2 is a peferct square so that always tells that this will invole in a square root to slove

14. godorovg

you could use a^2+B^2=c^2 as well

15. treydwg

So I got -1.125, -1.125. Can I write -1.125^2. Or is this considered incorrect?

16. godorovg

yes you can do that with 1.125^2 if you used the Quad form you would plus ninus which is what the problem is asking for..

17. treydwg

Ok i just wrote it twice. lets see if it counts it correct?

18. godorovg

treydwg first thing to know in this problem 64s^2+144s+81=0 all of the numbers are perfect squares. what that means taking the square root will be a number for example you take square root of 81 which is, we can check this by 9^2 and yes it equals 9.

19. treydwg

ok

20. treydwg

what about 2v^2+7v+5 and I need tofactor by grouping?

21. treydwg

I am at (2v^2+5v)(2v+5) and stuck

22. treydwg

@godorovg can you assist?

23. godorovg

yes

24. treydwg

where do I go from here?

25. godorovg

in this problem we need to use F,.O.I .L

26. treydwg

ok yes

27. godorovg

so now take the 2v^2 and times to 2v what is the answer

28. treydwg

4v^2

29. godorovg

close try again

30. godorovg

4v is right your power is wrong

31. treydwg

where are you getting the 2v^2*2v?

32. godorovg

because you typed 4v^2 while ago

33. godorovg

recall the problem here (2v^2+5v)(2v+5)

34. treydwg

yes that what I have

35. treydwg

2v(v+5)

36. treydwg

the (2v+5) is where im stuck

37. treydwg

what can I factor out of that?

38. godorovg

now 4v is right because 2v times 2v =4v^2 but that is not what is happening here. You have a power being times by V what is the power of the V? that power of the V is ^1 and when times 2v^2 time 2v = 4v^3

39. godorovg

so what happened here is we times the 2's to get 4 and v^2 + v^1 =V^3 see that

40. treydwg

let me look at that hold on

41. treydwg

ok I see it

42. treydwg

now how do I fix the last part?

43. godorovg

if you have a question plz ask me..

44. godorovg

factoring will not be in use unti we finish F.O.I.L

45. treydwg

I have (2v+5) how can I faactor this

46. godorovg

no you can not factor that..

47. treydwg

ok I see now so this is what I have after foil 4v^3+10v^2+35v

48. godorovg

now we can factor

49. treydwg

oooooooooh

50. treydwg

by grouping?

51. godorovg

no grouping there are no a like terms here

52. treydwg

I know but i was going to use 35v and try to make another number to group

53. godorovg

can not do that srry

54. treydwg

ok so wehre from here

55. treydwg

no GCF in common

56. godorovg

okay let us look at this 4v^3+10v^2+35v what is the same with all the numbers?

57. treydwg

v

58. godorovg

yes V so how many V's can be factored?

59. treydwg

1

60. treydwg

v(2v^2+10v+35)

61. godorovg

now look at the numbers what can each number be divided by?

62. treydwg

v(4v^2+10v+35)

63. godorovg

that is the answer it can not be factored any further

64. treydwg

ahhhhhhh! Thats my problem i want to always factor further :/

65. treydwg

Thank you

66. godorovg

treydwg here is a help for you, if you have done all the factoring right than find a number that divides in to the first and see if it works for example 2 will go ino 4 =2 2 will also go into 10 five times but here is a question for you will 2 divide even into 35?

67. godorovg

if the answer is no than you are finished..

68. treydwg

no it wont and that was my problem

69. treydwg

thanks

70. godorovg

welcome anytime

71. godorovg

before I leave any questions plz ask me

72. treydwg

thanks

73. treydwg

working on another

74. godorovg

If you need help I am here

75. treydwg

5x-3=14x+6 I got x=-1

76. godorovg

no

77. godorovg

5x-3=14x+6 get a like terms together so we x terms let us put the tgether like this 14x-5x=6-3 recall when a + or - crosses the equals sign it changes

78. treydwg

x=3/9??

79. godorovg

yes that is right

80. treydwg

ok i did that one a little wrong thank you

81. treydwg

now this one is throwing me off cuz the a^2 I have a^2=10-3a I got a^2=5/2

82. godorovg

83. treydwg

ok

84. godorovg

first off you can not a^2 = 10 -3a and come out with a^2=5/2 no..

85. godorovg

hint what happens to the problem when all nunbers are moved like this a^2+3a-10= what is this problem?

86. treydwg

um

87. godorovg

what did I say when a problem is set to zero is?

88. treydwg

nothing is on one side

89. treydwg

or they are all on one side rather

90. treydwg

have to factor?

91. godorovg

recall the problem a^2 = 10 -3a now look at the problem a^2+3a-10=

92. treydwg

0

93. treydwg

we have to find something in common

94. godorovg

so what type of problem is this? not factoring

95. treydwg

96. godorovg

yes

97. treydwg

so i need to find out what two numbers product is 10 and sum is 3 right?

98. godorovg

yes but I will let you try this way.

99. treydwg

k

100. godorovg

don't forget the a^2

101. treydwg

a^2-2a+5a-10=0

102. treydwg

(a+5)(a-2)

103. godorovg

GREAT JOB!!!

104. treydwg

awesome thank you again!

105. treydwg

so the solution set is (a+5)(a-2)?

106. godorovg

now I want you to check this

107. treydwg

k how do I check?

108. godorovg

simply take this (a+5)(a-2) use F.O.I.L and see if you get this back a^2+3a-10=

109. godorovg

if you do than you are right..

110. treydwg

alright

111. godorovg

did you get it?

112. godorovg

treydwg if you need help let me know..

113. treydwg

now I got this one wrong? dont know why? r^2+2r-48 I got (r+8)(r-6)

114. treydwg

sorry working on another one

115. godorovg

which the - to 8 and try again

116. treydwg

but 6-8 = -2 and not 2

117. godorovg

try both -

118. treydwg

that gives me a +48 and not -48

119. treydwg

i am pretty sure im right but the computer counted it wrong??

120. godorovg

treydwg is this a test?

121. treydwg

yeah but I have three times to take

122. treydwg

I can not figure this out and i know im right!

123. treydwg

can you figure out why its wrong?

124. godorovg

give me a minute

125. treydwg

I have already taken the test. just reviewing results

126. godorovg

okay that is better, I can get big trouble for helping on tests..

127. godorovg

because you have taken it already no worries

128. treydwg

yes all done and really confused because my answers I beleive are correct. There are many more like that. Have you figured out why im wrong?

129. godorovg

working on it

130. treydwg

thank you

131. godorovg

okay try 24 times and see what happens and work it again

132. godorovg

2

133. godorovg

24 times 2?

134. treydwg

k

135. godorovg

friends are here

136. godorovg

brb for me I have company over will back soon

137. treydwg

thank you