Question

1. 3x²+2x-5=0 2. 7x²-5x-2=0
3. x²+5x-14=0

решить через дискриминант !

Answer 1

$3x²+2x-5=0 \\ \\ d = {2}^{2} - 4 \times - 5 \times 3 = 64 = {8}^{2} \\ \\ x1 = \frac{ - 2 + 8}{3 \times 2} = \frac{6}{6} = 1 \\ x2 = \frac{ - 2 - 8}{3 \times 2} = \frac{ - 10}{6} = - \frac{5}{3}$

$7x²-5x-2=0 \\ \\ d = { - 5}^{2} - 4 \times 7 \times - 2 = 81 = {9}^{2} \\ \\ x1 = \frac{5 + 9}{7 \times 2} = 1 \\ \\ x2 = \frac{5 - 9}{7 \times 2} = \frac{ - 4}{14} = - \frac{2}{7}$

$x²+5x-14=0 \\ \\ d = {5}^{2} - 4 \times - 14 = 81 = {9}^{2} \\ \\ x1 = \frac{ - 5 + 9}{2} = 2 \\ \\ x2 = \frac{ - 5 - 9}{2} = - 7$

извини что долго