2x²-5x-3=0

3x²+16x-12=0

4x²+8a-32=0

V-квадратный корень

2x²-5x-3=0

D = ( - (-5)) ^2-4*2 * (-3) = 25 - (-24) = 25+24=49

x1 = ( - (-5) - V49) / 2*2 = (5-7) / 4=-2/4=-1/2

x2 = ( - (-5) + V49) / 2*2 = (5+7) / 4=12/4=3

3x²+16x-12=0

D = (-16) ^2-4*3 * (-12) = 256 - (-144) = 256+144=400

x1 = (-16-V400) / 2*3 = (-16-20) / 6=-36/6=-6

x2 = (-16+V400) / 2*6 = (-16+20) / 6=4/6=2/3

4x²+8a-32=0

4x^2=32-8a

4x^2=4 (8-2a) |:4

x^2 = (8-2a)

x1=-V (8-2a)

x2=V (8-2a)