5ab-7b-5a²-7a=5 *(-13,69)-7*(-3,7)-5*13,69-7*3,7=-68,45+25,9-68,45-25,9=-136,9
1) 4-3х=-7х-4 3)9+5(4х-3)=7х-6
-3х+7х=-4-4 9+20х-15=7х-6
4х=-8 20х-7х=-6-9+15
х=-8:4 13х=0
х=-2 х=0
2) 7х=5+2(6х-5) 4) 25-(3х+5)=7(4х+3)
7х=5+12х-10 25-3х-5=28х+21
7х-12х=5-10 -3х-28х=21-25+5
-5х=-5 -31х=1
х=-5:-5 х=-
х=1
5) 6(2х+7)-2(6х-5)=3х-2 6)11(х-2)-(2х-3)=9(х+2)
12х+42-12х+10=3х-2 11х-22-2х+3=9х+18
12х-12х-3х=-2-42-10 11х-2х-9х=18+22-3
-3х=-54 0х=37
х=-54:(-3) х - любое число
х=18
5,125х - 3х - 11 = 47 - 37/8х
х = 8 целых 16/27
x=6-y
6-y+y+y(6-y)²+y²(6-y)=24
6+y³-12y²+36y+6y²-y³=24
-6y²+36y-18=0
y²-6y+3=0
D= 36-12= 24
y1= (6+√24)/2= 3+√6
y2= (6-√24)/2= 3-√6
x1= 6-3-√6= 3-√6
x2= 6-3+√6= 3+√6
пары чисел: (3-√6;3+√6) и (3+√6;3-√6)