х²+3х-28=x²+7x-4x-28=x(x+7)-4(x+7)=(x+7)(x-4)
x^2 + 3x - 28=0
D=b^2-4ac=9+112=121^2=11
x1=(-3-11)/2=-7
x2=(-3+11)/2=4
х²+3х-28=x²+7x-4x-28=x(x+7)-4(x+7)=(x+7)(x-4)
x^2 + 3x - 28=0
D=b^2-4ac=9+112=121^2=11
x1=(-3-11)/2=-7
x2=(-3+11)/2=4