Question

А) x(x-15)=16 решите уравнение

Answer 1

х (х - 15) = 16
х^2 - 15х = 16
х^2 - 15х - 16 = 0
D = b^2 - 4 * a * c = -15^2 - 4 * 1 * (-16) = 225 + 64 = 289
x1/2 = (-b +/- √D)/(2 * a)
x1/2 = (-(-15) +/-17)/(2 * 1)
x1/2 = (15 +/-17)/2
x1 = (15 + 17)/2
x1 = 32/2
x1 = 16
x2 = (15 - 17)/2
x2 = - 2/2
x2 = -1.