Solve for p1 p_1v_1=p_2v_2

$p_{1} v_{1} = p_{2} v_{2}$

Divide each term in $p_{1} v_{1} = p_{2} v_{2}$ by $v_{1}$ .

$\frac{p_{1} v_{1}}{v_{1}} = \frac{p_{2} v_{2}}{v_{1}}$

Simplify the left side.

Cancel the common factor of $v_{1}$ .

Cancel the common factor.

$\frac{p_{1} v_{1}}{v_{1}} = \frac{p_{2} v_{2}}{v_{1}}$

Divide $p_{1}$ by $1$ .

$p_{1} = \frac{p_{2} v_{2}}{v_{1}}$