## anonymous one year ago y = 5 y = 3x - 4 PLEASE HELP ME WITH 3 QUESTIONS THAT'S ALL JUST 3!!

1. Michele_Laino

here we can write this: $\Large 3x - 4 = 5$

2. anonymous

Okay

3. Michele_Laino

now I add 4 to both sides: $\Large 3x - 4 + 4 = 5 + 4$ please continue

4. anonymous

3,9

5. anonymous

is 3,9 right or is it wrong what is it , I'm really frustrated so ....

6. Michele_Laino

after a simplification, we can write: $\Large 3x = 9$

7. Michele_Laino

now, please divide by 3, both sides

8. anonymous

what sides am I dividing it by

9. anonymous

I got 3

10. Michele_Laino

hint: |dw:1437154156003:dw|

11. Michele_Laino

that's right!

12. anonymous

so is it 3,3

13. Michele_Laino

it is x=3

14. anonymous

I have to write it as an ordered pair

15. Michele_Laino

ok! we have: x=3 and y=5, so we can write: (3,5)

16. anonymous

Find the solution(s) to the system, if one or more exist. Write your answer as an ordered pair. Round to the nearest hundredth, if necessary. \begin{array}{l}y = {x^2} + 4x - 3\\x = 1\end{array} this is the other one, I have one more I need help on

17. Michele_Laino

we have to substitute x=1 into the first equation, so we can write: $y = {1^2} + 4 \times 1 - 3 = ...?$

18. anonymous

okay

19. Michele_Laino

please continue, what is y?

20. anonymous

42

21. anonymous

that;s what I got for y

22. Michele_Laino

hint: $y = {1^2} + 4 \times 1 - 3 = 1 + 4 - 3 = ...?$

23. anonymous

I got 3, 2

24. Michele_Laino

we have: y=2 and x=1 so we can write: (1,2)

25. anonymous

is that the answer?

26. Michele_Laino

yes!

27. anonymous

Explain how to find the solution(s) to the system. Give the solutions(s) as ordered pairs rounded to the nearest hundredth, if necessary. \begin{array}{l}y = - 0.5{x^2} + x + 6\\y = 3.25\end{array} this is the last question I need help on I need help finding the ordered pairs

28. Michele_Laino

we have to apply the transitive property, so we can write: $\Large - 0.5{x^2} + x + 6 = 3.25$

29. anonymous

ok

30. Michele_Laino

it is a quadratic equation, since we can rewrite it as follows: $\Large 0.5{x^2} - x - 2.75 = 0$

31. anonymous

ok

32. Michele_Laino

or using fraction instead decimal numbers, we get: $\Large \frac{{{x^2}}}{2} - x - \frac{{11}}{4} = 0$

33. anonymous

ok

34. Michele_Laino

now, I multiply both sides by 4, so I can write: $\Large \begin{gathered} 4 \times \left( {\frac{{{x^2}}}{2} - x - \frac{{11}}{4}} \right) = 0 \times 4 \hfill \\ 4 \times \frac{{{x^2}}}{2} + 4 \times \left( { - x} \right) + 4 \times \left( { - \frac{{11}}{4}} \right) = 0 \hfill \\ 2{x^2} - 4x - 11 = 0 \hfill \\ \end{gathered}$

35. anonymous

ok

36. Michele_Laino

note that equation is an equation like this: $\Large a{x^2} + bx + c = 0$ where: $\Large \begin{gathered} a = 2 \hfill \\ b = - 4 \hfill \\ c = - 11 \hfill \\ \end{gathered}$

37. anonymous

okay

38. Michele_Laino

so we can apply the standard formula: $\Large x = \frac{{ - b \pm \sqrt {{b^2} - 4 \times a \times c} }}{{2 \times a}}$

39. Michele_Laino

in order to find the values of x

40. anonymous

okay

41. Michele_Laino

after a simple substitution, we get: $\large \begin{gathered} x = \frac{{ - b \pm \sqrt {{b^2} - 4 \times a \times c} }}{{2 \times a}} = \frac{{4 \pm \sqrt {{{\left( { - 4} \right)}^2} - 4 \times 2 \times \left( { - 11} \right)} }}{{2 \times 2}} = \hfill \\ \hfill \\ = \frac{{4 \pm \sqrt {16 + 88} }}{4} \hfill \\ \end{gathered}$ please continue

42. anonymous

I got 7

43. Michele_Laino

hint: we have 2 values for x: $\Large \begin{gathered} {x_1} = \frac{{4 + \sqrt {16 + 88} }}{4} = ...? \hfill \\ \hfill \\ {x_2} = \frac{{4 - \sqrt {16 + 88} }}{4} = ...? \hfill \\ \end{gathered}$

44. anonymous

42

45. Michele_Laino

hint: $\begin{gathered} {x_1} = \frac{{4 + \sqrt {16 + 88} }}{4} = \frac{{4 + \sqrt {104} }}{4} = \frac{{4 + 10.2}}{4} = \frac{{14.2}}{4} = ...? \hfill \\ \hfill \\ {x_2} = \frac{{4 - \sqrt {16 + 88} }}{4} = \frac{{4 - \sqrt {104} }}{4} = \frac{{4 - 10.2}}{4} = \frac{{ - 6.2}}{4} = ...? \hfill \\ \end{gathered}$

46. anonymous

14.24 -6.24

47. Michele_Laino

you have to divide by 4, namely 14.20/4=...? -6.20/4=...?

48. anonymous

3.55 , 1.55

49. anonymous

-1.55

50. Michele_Laino

we have: x1= 3.55 x2=-1.55

51. Michele_Laino

ok!

52. anonymous

ok

53. Michele_Laino

so the requested pairs, are: (3.55, 3.25) (-1.55, 3.25)

54. anonymous

Thank you

55. anonymous

i need two that I wanted you to check

56. Michele_Laino

ok!

57. anonymous

Find the solution(s) to the system, if one or more exist. Write your answer as an ordered pair. \begin{array}{l}y = 3{x^2} + 2x + 4\\x = 4\end{array} I have 156,4 as my answer

58. Michele_Laino

substituting x=4 into the first equatiuon, we get: $y = 3 \times {4^2} + 2 \times 4 + 4 = 3 \times 16 + 8 + 4 = 48 + 12 = 60$

59. Michele_Laino

so the requested pair is: (4, 60)

60. anonymous

one of the answer they have is (4,60) and (60 ,4)

61. anonymous

thank you

62. Michele_Laino

:)

63. anonymous

the one with 3,5 wasn't right

64. anonymous

right

65. Michele_Laino

please what question do you refer to?