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