Ответ:
а) 5x²+14x-3=0
D=b²-4ac=14²-4*5*(-3)3=196 + 60=256 (√D=16)
x₁ = \frac{-b+ \sqrt{D} }{2a}2a−b+D = \frac{-14+16}{2*5} = \frac{2}{10}2∗5−14+16=102 = 0,2
x₂= \frac{-b- \sqrt{D} }{2a}2a−b−D = \frac{-14-16}{2*5} = \frac{-30}{10}2∗5−14−16=10−30 = -3
б) 36x²-25=0
36х²=25
х²= \frac{25}{36}3625
х = ± \sqrt{ \frac{25}{36} }3625
х₁ = \frac{5}{6}65
х₂= - \frac{5}{6}65
в) 4x²=16x
4х²-16х=0
4х(х-4)=0
4х=0
х₁=0
х-4=0
х₂=4
г) (x-3)²-2(x-3)-15=0
х²-2*3*х+3² - 2х+6-15=0
х²-6х+9-2х+6-15=0
х²-8х=0
х(х-8)=0
х₁=0
х-8=0
х₂=8