Question

if a^2+b^2=60 and a-b=5 find ab.​

Answer 1

$( {a - b})^{2} = {5}^{2} \\ {a}^{2} + {b}^{2} - 2ab = 25 \\ 60 - 2ab = 25 \\ 2ab = 60 - 25 \\ ab = \frac{35}{2} \\ ab = 17.5$