1
m²+20m+100-n²+24n-144=m²-n²+20m+24n-44
c²+38cd+361d²-361d²-38cd-d²=c²-d²
2
a²+ab+ac+ab+b²+bc+ac+bc+c²=а²+2ab+b²+2аc+2bс+с²<span>
a</span>²+2ab+b²+2ac+2bc+c²=а²+2ab+b²+2аc+2bс+с²
тождество верно
5х^2-2x^2+5x-11x-15-9=0
3x^2-6x-24=0
x^2-2x-8=0
d=4+32=36
x=4
x=-2
<span>3(2x-y)+2(x+4y)-5(2x-3y) = 6x-3y+2x+8y-10x+15y=-2x+20y</span>