**7. Simplify the following, combining like terms: {2[-4(x-y)+5]-(9x-y)}-[-2(y+3x)]**

Ans.

{2[-4(x-y)+5]-(9x-y)}-[-2(y+3x)]={2[-4x+4y+5]-9x+y}-[-2y-6x]

={-8x+8y+10-9x+y}+2y+6x

=-17x+9y+10+2y+6x

=-11x+11y+10

11x-11y=10

**8. Simplify the following, combining like terms: (5w^3-4w)(w^2-2w+9)**

Ans.

(5w^3-4w)(w^2-2w+9)=5w^5-10w^4+45w^3-4w^3+8w^2-36w

=5w^5-10w^4+41w^3+8w^2-36w

**9. Simplify the following: 19+3^4-6-〖(-3+9)〗^2**

Ans.

19+3^4-6-(-3+9)^2=19+81-6-36=58

**10. Determine whether the ordered pair (-7,8) is a solution to: -8x+y = 64**

Ans.

-8x+y = 64

y=8x+64

8=8(-7)+64

8=-56+64

8=8

**11. Find the slope of the line that goes through the two points: (-5,8) and (-4,9)**

** Ans.**

m=(y_2-y_1)/(x_2-x_1 )=(9-8)/(-4-(-5))=1/(-4+5)=1/1=1

**12. Find the y-intercept of: -7y + x – 1 = 5x + 15**

Ans.

-7y = 4x + 16

Divide with -7

y=-4/7 x-16/7

The y intercept is -16/7