(a-4)(-6)=-5a-24-7
-6a+24=-5a-31
-a=-55
a=55
ответ: при а=55
1.
а) x²-2x-8
б) 8a²+10ab-3b²
в) y³-7y²+13y-15
2.
a) (x-y)(a+4)
б) (x-y)(3+a)
3.
y²-yb-ya+ab=y²-yb-ya+ab
4.
y(y+3)=0
y1=0
y2=-3
Вот)........................
X^3-3x^2+3x-1 =x^3-3x^2*1+3x*1^2-1^3=<span> (x-1)^3
</span>0,25x^2+y^2-xy = (0,5x)^2 -2*0,5x*y+y^2 = (0,5x-y)^2
<span>60x^2+30x+45 =15(4x^2+2x+3)
</span><span>(6x-8)^2= [2(3x-4)]^2 = 4(3x-4)^2
* = 4
</span>