Question 168672
1.(2a-7)(a+9)=0

The solution to this quadratic equation is a=7/2 or a=-9

You need to set each factor to equal 0.


2.64x^2-9=0
Add 9 to both sides


Divide both sides by 64

x^2=9/64

Take the sq rt of the numerator and denominator 

x=3/8

3.x(x+3)=18

Use the distributive property

x^2+3x=18

Subtract 18 from both sides


x^2+3x-18=0


This equation can be easily factored into

(x+6)(x-3)=0

The solutions for this quadratic equation are x=-6 and x=3

1.2ab+2ay+bx+xy

2a(b+y)+x(b+y)

since both terms contain b+y

you can then redistribute the terms (a+x)(b+y)

To double check use the FOIL method and see that you have the same equation you started with.