Step-by-step explanation:
7. x^2 - 4x
a= 1
b= -4
c= 0
8. 2x^2 -3x +1
a= 2
b= -3
c= 1
9. 9x^2 - 4
a= 9
b= 0
c= -4
10. x^2 +12x +36
b= 12
c= 36
11. x^2 -9x + 9
b= -9
c= +9
12. - (x^2 + 10x + 25)
= -x^2 -10x - 25
a= -1
b= -10
c= -25
