Question

27 squared = 729, and i have to use (a + b) sqaured = a sqaured + 2ab + b squared

Answer 1

27² = 729

Using the form;

(a + b)² = a² + 2ab + b²

we can break 27 into (20 + 7)

So that we have;

(20 + 7)² = 20² + 2(20)(7) + 7²

= 400 +280 + 49

=729