Question

Find the product, using suitable properties:(–57) × (–19) + 57

Answer 1

To find the product, using suitable properties:
(–57) × (–19) + 57

By inspecting the expression one can analyze that 57 occurs in both the terms,so if we take 57 common then it becomes very easy to calculate.

$( - 57) \times ( - 19) + 57 \\ \\ = ( - \times - ) 57 \times 19 + 57 \\ \\ = 57 \times 19 + 57 \\ \\ =57(19 + 1) \\ \\ = 57 \times 20 \\ \\ = 1140$
as we know that (-)×(-) = +