# How do you solve for J in (CE)/2 = (3JQ)/7?

Jul 5, 2017

$J = \frac{7 C E}{6 Q}$

#### Explanation:

1. Cross multiply.

Multiply the numerator of the first fraction by the denominator of the second fraction, and set that equal to the numerator of the second fraction times the denominator of the first fraction. For example:

$\frac{a}{b} = \frac{c}{d}$

$a d = b c$

$\frac{C E}{2} = \frac{3 J Q}{7}$

$7 \left(C E\right) = 3 J Q \left(2\right)$

$7 C E = 6 J Q$

Commutative property:

$7 C E = 6 Q J$

2. To isolate J, divide both sides by 6Q.

$\frac{7 C E}{6 Q} = \frac{\cancel{6 Q} J}{\cancel{6 Q}}$

$\frac{7 C E}{6 Q} = J$

You've now solved for J. Hope this helps!