Use the substitution property of equality to complete the following statement if y=3 and 8x+y=12,then_
a)3-y=12
b)8(3)-y=12
c)8x-3=12
d)8x+3=12
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The answer is D)

Step-by-step explanation:

In order to determine the correct option, we have to know about the substitution property.

The substitution property is when we replace the variable of the equation by a number. For example:

Given

In this example, we applied the substitution property replacing the "x" variable by 3.

For this case:

So, the final expression is matching with the D) option.

Finally, the correct answer is D)

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