Given the equation, 3c - 9 = 21 + 7, what would be an appropriate first step?
subtract 2x from both sides
Subtract 9 from both sides
add 7 to both sides
add 3x to both sides

a) 7x=7

step-by-step explanation:

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

y - 25 = 2 ( x - 10 ) should be the answer