Question

розв'яжіть рівняння
3. (2x-7)(2x+7)= x(4x+3);
4. (x+2)2 = (x - 4)(x + 4);

Answer 1

$(2x - 7)(2x + 7) = x(4x + 3) \\ (2x) {}^{2} - 7 {}^{2} = 4 {x}^{2} + 3x \\ 4 {x}^{2} - 49 - 4 {x}^{2} - 3x = 0 \\ - 3x - 49 = 0 \\ 3x + 49 = 0 \\ 3x = - 49 \\ x = - 49 \div 3 \\ x = - 16 \times \frac{1}{3} \\ \\ \\ (x + 2) {}^{2} = (x - 4)(x + 4) \\ {x}^{2} + 4x + 4 = {x }^{2} - 16 \\ {x {}^{2} + 4x + 4}^{} - {x}^{2} + 16 = 0 \\ 4x + 20 = 0 \\ 4x = - 20 \\ x = - 20 \div 4 \\ x = - 5$