Examples
x=5yx=5y , y=13y=13 , y=2y=2
Step 1
When two variable quantities have a constant ratio, their relationship is called a direct variation. It is said that one variable varies directly as the other. The formula for direct variation is y=kxy=kx, where kk is the constant of variation.
y=kxy=kx
Step 2
Solve the equation for kk, the constant of variation.
k=yxk=yx
Step 3
Replace the variables xx and yy with the actual values.
k=135yk=135y
Step 4
Multiply the numerator by the reciprocal of the denominator.
k=13⋅15yk=13⋅15y
Step 5
Step 5.1
Multiply 1313 by 15y15y.
k=13(5y)k=13(5y)
Step 5.2
Multiply 55 by 33.
k=115yk=115y
k=115yk=115y
Step 6
Use the formula x=kyx=ky to substitute 115y115y for kk and 22 for yy.
x=(115(2))⋅(2)x=(115(2))⋅(2)
Step 7
Step 7.1
Multiply 115(2)115(2) by 22.
x=115(2)⋅(2)x=115(2)⋅(2)
Step 7.2
Multiply 115(2)115(2) by 22.
x=115(2)⋅2x=115(2)⋅2
Step 7.3
Remove parentheses.
x=(115(2))⋅(2)x=(115(2))⋅(2)
Step 7.4
Simplify (115(2))⋅(2)(115(2))⋅(2).
Step 7.4.1
Multiply 1515 by 22.
x=130⋅2x=130⋅2
Step 7.4.2
Cancel the common factor of 22.
Step 7.4.2.1
Factor 22 out of 3030.
x=12(15)⋅2x=12(15)⋅2
Step 7.4.2.2
Cancel the common factor.
x=12⋅15⋅2
Step 7.4.2.3
Rewrite the expression.
x=115
x=115
x=115
x=115