Write in factored form:

3x^2-20=+7x

a: (3x-5)(x+4)=0
b: 3(x+5)(x-4)=0
c: (3x-7)(x-20)=0
d: 3x=5)(x-4)=0

( 3x + 5 ) ( x - 4 )

Step-by-step explanation:

1.) Factors of 20 = (1,20) (2,10) and (4,5)

2.) ( 3x + 5 ) ( x - 4 )

3.) 3x - 12x + 5x - 20 = 0

4.) 3x^2 + 7x - 20 = 0

step-by-step explanation:

the ratio of red paint to blue paint is always 9/7. that means that, whatever x's value, (4x+12)/(4x-4) has that same ratio. so, set up an equation and cross-multiply to solve for x:

9/7 = (4x+12)/(4x-4)

9(4x-4) = 7(4x+12)

36x - 36 = 28x + 84

8x - 36 = 84

8x = 120

x = 15