Решить уравнение x^2-7x-18=0 x^2+x-6=0 x^2+3x-130=0 4x^2-4x-3=0

X^2 - 7x - 18 = 0
D = b^2 - 4ac = 49 + 72 = 121 = 11^2
x1 = ( 7 + 11) / 2 = 9
x2 = ( 7 - 11) / 2 = - 2

x^2 + x - 6 = 0
D = b^2 - 4ac = 1 + 24 = 25 = 5^2
x1 = ( - 1 + 5) / 2 = 2
x2 = ( - 1 - 5) / 2 = - 3

x^2 + 3x - 130 = 0
D = b^2 - 4ac = 9 + 520 = 529 = 23^2
x1 = ( - 3 + 23) / 2 = 10
x2 = ( - 3 - 23) / 2 = - 13

4x^2 - 4x - 3 = 0
D = b^2 - 4ac = 16 + 48 = 64 = 8^2
x1 = ( 4 + 8) / 8 = 1,5
x2 = ( 4 - 8) / 8 = - 0,5