Question

Expand the following using suitable Identity
(x+20) (x-20) and (x+12)(x+12)

Answer 1

Answer:

(i) x² - 400

(ii) x² + 24x + 144

Step-by-step explanation:

(i) Using the following identity

$(a + b)(a - b) = {a}^{2} - {b}^{2}$

Where a = x and b = 20

$(x + 20)(x - 20) = {(x)}^{2} - {(20)}^{2}$

$= {x}^{2} - 400$

(ii) We can also write

$(x + 12)(x + 12)$

as

${(x + 12)}^{2}$

Using the following identity

${(a + b)}^{2} = {a}^{2} + 2ab + {b}^{2}$

Where a = x and b = 12

${(x + 12)}^{2} = {(x)}^{2} + (2 \times x \times 12) + {(12)}^{2}$

$= {x}^{2} + 24x + 144$

Answer 2

Step-by-step explanation:

(x+20) (x-20)

=x square-(20*20)

=x square-400(and)