## anonymous one year ago Choose the correct simplification of the expression -5x2(4x - 6x2 - 3). 30x4 - 20x3 + 15x2 -11x4 - x3 - 8x2 -30x4 + 20x3 - 15x2 30x4 + 20x3 + 15x2

1. Nnesha

multiply everything which is inside the parentheses by outside term and when you multiply same bases you should add their exponents

2. triciaal

also pay attention to the signs

3. anonymous

i still don't understand :(

4. Nnesha

example a(b+c) multiply b and c by outside term which is a a times b + a times c =ab+ac

5. Nnesha

multiply all 3 terms 4x,-6x^2 ,-3 by -5x^2

6. anonymous

Will it end up negative or positve?

7. Nnesha

you have to multiply 2 terms if one of them is negative then answer will be negative negative times negative =positive negative times positive = negative

8. Nnesha

-5x^2 times 4x =??

9. anonymous

so this one will end up negative because the outside term is negative?

10. anonymous

Cant you not combine them because one has an exponent and the other doesn't

11. Nnesha

you will get 3 terms and all of them end up with different signs bec it also depends on inside terms

12. Nnesha

yes right in order to combine them you u should have same variable with same exponents x^2 +x you can't combine these both terms bec both hve different exponents

13. Nnesha

-5x^2 times 4x = (-5 times 4)(X^2 times x) add exponents so it should be like this x^{2+1}

14. anonymous

I'm so confused

15. Nnesha

|dw:1437425764823:dw|

16. Nnesha

$-5x^2 \times 4x = what ?$

17. anonymous

-20^3?

18. Nnesha

not -20 to the 3 power x^3

19. anonymous

how?

20. Nnesha

multiply numbers together $\huge\rm \color{reD}{-5}x^2 \times \color{ReD}{4}x =(\color{ReD}{-5 \times 4)}x^{2+1}$

21. Nnesha

x^2 times x = x^{2+1} not 20.. "=-

22. Nnesha

so it's -20x^3

23. Nnesha

now multiply by other 2 terms

24. anonymous

i still don't understand how your getting what your getting

25. Nnesha

how i got what ?

26. Nnesha

we have to multiply -5x^2 by all 3 terms 4x times -5x^2 -6x times -5x^2 -3 times -5x^2

27. Nnesha

when you multiply same bases then you should add their exponents $\huge\rm x^m \times x^n =x^{m+n}$

28. Nnesha

let me know if u r still confusd