## spidergirl51 2 years ago (5x-8) (2x-5)

1. math456

5x(2x-5)-8(2x-5) <-- try to solve this

2. spidergirl51

um

3. math456

use multiplication

4. spidergirl51

okay i got 10x-25 -16x+40

5. andrea408

10x^2-25x-16x+25 which would be 10x^2-41x+25

6. math456

great now solve further..

7. johnweldon1993

Correct but remember 10x is 10 x ²

8. spidergirl51

um

9. spidergirl51

idk what to do now

10. math456

yea when u multiply x's it becomes square

11. math456

x.x=x^2

12. johnweldon1993

When you multiply 2 numbers with x's the x's multiply too...which becomes x times x which is x squared...or x²

13. spidergirl51

10x2

14. spidergirl51

and then what

15. spidergirl51

16. spidergirl51

-4x2

17. math456

now u hv 10x^2-41x+25.. after adding x's

18. spidergirl51

i mean -6x2

19. johnweldon1993

16x stays the same...do you have any other x's? ***you cannot combine x² and x.

20. spidergirl51

oh

21. johnweldon1993

wait perhaps I've looked wrong let me do this out

22. spidergirl51

so its 10x2 -41x+25

23. johnweldon1993

(5x-8) (2x-5) 10x² - 25x - 16x + 40 so yes 10x² -41x + 40

24. spidergirl51

i have like 13 problems like these

25. math456

did u get some idea how to do it?

26. spidergirl51

27. math456

Use the FOIL method i used above for this e.g

28. spidergirl51

(7w+5)(11w-3)

29. math456

let me do it over: 5x(2x-5)-8(2x-5) 10x^2-25x-16x+40 10x^2-41x+40

30. spidergirl51

so 77w2+55w-33w-15

31. math456

yea use the same trick with this: 7w(11w-3)+5(11w-3) <- they just replaced x with w's

32. spidergirl51

is that right

33. math456

u got first one right 7w x 3 = 21w

34. math456

so it will be 77w^2-21w+55w-15 77w^2+34w-15

35. spidergirl51

yup the next one is *b-2)(b2-b+1)

36. math456

try it..

37. math456

b(b^2-b-1)-2(b^2-b+1)

38. spidergirl51

um

39. math456

its not tht hard, give it a try

40. spidergirl51

i got 2b2-2b-1b-2b2-2b+2

41. math456

ur second part is right..

42. spidergirl51

my first part is wrong

43. math456

when u multiply bxb^2 it will be b^3

44. spidergirl51

so its b3

45. math456

right!

46. math456

same goes with the next one.. u just add power to the variable when u multiply

47. spidergirl51

so what will it look i like

48. math456

b(b^2-b-1)-2(b^2-b+1) \[b ^{3}-b ^{2}-b-2b ^{2}+2b-2\]

49. spidergirl51

can you solve that