X^2 + x - 56 = 0
D = b^2 - 4ac = 1+ 224 = 225
√D = 15
x1 = (-1 + 15) /2 = 7
х2 = (-1 - 15) /2 = -16/2 = -8
10×(7,6-434)=434-76=358×10=3580
<span>у=log₂₀(x²-x)
</span>log₂₀(x²-x)>0
x²-x>1
x²-x-1 = (x-1/2+√5/2)(x-√5/2-1/2)>0
x∈(-∞, 1/2-√5/2)⋃(√5/2+1/2, ∞)
3х^2 -(3х-1)(х+2)=3х^2 - (3х^2+6х-х-2)=3х^2 - 3х^2 +5х-2=5х-2=5*(-3)-2=-15-2=-17