Question

expand using suitable identity (2a+5b)^2​

Answer 1

Answer:

(2a + 5b)²

by using identity

(a + b)² = a² + b² + 2ab

(2a)² + (5b)² + 2*2a*5b

4a² + 25b² + 20ab

HOPE IT WILL HELP YOU

Answer 2

(2a + 5b)² = 4a² + 20ab + 25b²

Given :

The expression (2a + 5b)²

To find :

To expand using suitable identity

Formula :

(x + y)² = x² + 2xy + y²

Solution :

Step 1 of 2 :

Write down the given expression

The given expression is (2a + 5b)²

Step 2 of 2 :

Expand the expression

We use the identity (x + y)² = x² + 2xy + y²

We take x = 2a , y = 5b

Thus we get

$\sf {(2a + 5b)}^{2}$

$\sf = {(x + y)}^{2}$

$\sf = {x}^{2} + 2xy + {y}^{2}$

$\sf = {(2a)}^{2} + 2 \times 2a \times 5b + {(5b)}^{2}$

$\sf = 4{a}^{2} + 20ab + 25{b}^{2}$

∴ (2a + 5b)² = 4a² + 20ab + 25b²