ответ:
7y²+19y-6=0
d=19² - 4*7*(-6)=361+168=529=23²
y₁=(-19-23)/14=-42/14= -3
y₂=(-19+23)/14=4/14=2/7
7y²+19y-6=7(y - ²/₇)*(y+3)=(7y-2)(y+3)
