Multiply the numerator of the first fraction by the denominator of the second fraction. Set this equal to the product of the denominator of the first fraction and the numerator of the second fraction.

Simplify .

Apply the distributive property.

Multiply by .

Simplify .

Apply the distributive property.

Simplify the expression.

Move to the left of .

Multiply by .

Move all terms containing to the left side of the equation.

Subtract from both sides of the equation.

Subtract from .

Move all terms not containing to the right side of the equation.

Subtract from both sides of the equation.

Subtract from .

Multiply each term in by

Multiply each term in by .

Multiply .

Multiply by .

Multiply by .

Multiply by .

Solve for d 3/(d+3)=4/(d+12)