4212=21y

Rewrite the equation as 21y=4212.

21y=4212

Factor 6 out of 42.

21y=6(7)12

Cancel the common factors.

Factor 6 out of 12.

21y=6⋅76⋅2

Cancel the common factor.

21y=6⋅76⋅2

Rewrite the expression.

21y=72

21y=72

21y=72

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.

21⋅2=y⋅7

Rewrite the equation as y⋅7=21⋅2.

y⋅7=21⋅2

Multiply 21 by 2.

y⋅7=42

Divide each term by 7 and simplify.

Divide each term in y⋅7=42 by 7.

y⋅77=427

Cancel the common factor of 7.

Cancel the common factor.

y⋅77=427

Divide y by 1.

y=427

y=427

Divide 42 by 7.

y=6

y=6

y=6

Solve for y 42/12=21/y