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1) x2+14x+49-(x2-4x+4)=-15
x2+14x+49-x2+4x-4=-15
18x+45=-15
18x=-15-45
18x=-60
x=-3 целая 1/3
2) 16x2+40x+25+(24x+3-16x2-2x)=7
16x2+40x+25+24x+3-16x2-2x=7
62x+28=7
62x=7-28
62x=-21
x=-21/62
3) x(6x-x2+12-2x)=14-x(x2-4x+4)
x(4x-x2+12)=14-x3+4x2-4x
4x2-x3+12x=14-x3+4x2-4x
4x2-x3+12x+x3-4x2+4x=14
16x=14
x=0,875 или 7/8
4) 36x2-12x+1-(12x2+4x-9x-3)=6(4x2-20x+25)+113x
36x2-12x+1-(12x2-5x-3)=24x2-120x+150+113x
36x2-12x+1-12x2+5x+3=24x2-7x+150
24x2-7x+4=24x2-7x+150
24x2-7x-24x2+7x=150-4
0x=146
x= бесконечное множество ответов
5) x2-4=3(x2+8x+16)-2x2-10x
x2-4=3x2+24x+48-2x2-10x
x2-4=x2-14x+48
x2-x2+14x=48+4
14x=52
x=52/14