Question

simplify (7+5x)(7+5x) -(2x-3)(2x-3)​

Answer 1

Answer:

(5x + 13) (5x + 1)

Step-by-step explanation:

(7 + 5x) (7 + 5x) - (2 ×-3) (2 ×-3)

${(7 + 5x)}^{2} - {(2 \times - 3)}^{2}$

Expanding

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

$( {7}^{2} + 2 \times 7 \times 5x + {(5x)}^{2} ) - {( - 6)}^{2}$

$(49 + 70x + 25 {x}^{2} ) - (36)$

$49 - 36 + 70x + 25 {x}^{2}$

$13 + 70x + 25 {x}^{2}$

$25 {x}^{2} + 70x + 13$

Factorising

Product =25×13=325

Sum = 70

Numbers are 65 and 5

Substituting

$25 {x}^{2} + 65x + 5x + 13$

Taking common factors

$5x(5x + 13) + 1(5x + 13)$

Taking 5x + 13 as common

$(5x + 13)(5x + 1)$