<span>5а²-3а =5*(-3)²-3(-3)=5*9+9=45+9=54
</span><span>а)-4у+7у²2-5у+3у²=10у²-9у
б)-4х³х-2х•3у+15уу=-4х^4-6xy+15y²
</span><span>-2х+3х-7х=12
-6х=12
х=12:(-6)
х=-2
</span>
Ща будет
Д=(19)^2-4*1*48=361-192=169>0
x1= ДРОбЬ -19+13 = -3
2
x2= Дробь -19-13 = -16
2
2x^2+8-30x^2-120 = 0
-28x^2 - 112= 0
-28x^2=112
x^2= -4
x^2= +-2