Question

1. Решите уравнение: x²+3(x - 4)(x + 4) =(2x+3)2 +3​

Answer 1

${x}^{2} + 3(x - 4)(x + 4) = {(2x + 3)}^{2} + 3$

${x}^{2} + 3(x - 4)(x + 4) - {(2x + 3)}^{2} - 3 = 0$

${x}^{2} + 3( {x}^{2} - {4}^{2} ) - ( {(2x)}^{2} + 2 \times 2x \times 3 + {3}^{2} ) - 3 = 0$

${x}^{2} + 3( {x}^{2} - 16) - (4 {x}^{2} + 12x + 9) - 3 = 0$

${x}^{2} + 3 {x}^{2} - 48 - 4 {x}^{2} - 12x - 9 - 3 = 0$

$- 12x - 60 = 0$

$- 12x = 60$

$x = 60 \div ( - 12)$

$x = - 5$

Ответ: $x = - 5$