Question

# If $1 \times 2 = 32;4 \times 3 = 712;4 \times 7 = 1128$ then $5 \times 1 = ?$

$a \times b = \left( {a + b} \right)\left( {ab} \right)$
$5 \times 1 = \left( {5 + 1} \right)\left( {5 \times 1} \right)$
$5 \times 1 = 65$
Answer = $65$