1) в
2) б
3) г
4) 3/4y = 0.6x - 6
y = 0.6x*4/3 -6*4/3
y = 0.8x - 8
5) y= -0.75x
0.25x/2 +1.5x/3 = 2.5
0.125x+0.5x = 2.5
0.625x=2.5
x =4
y = -3
6) x^2-11x+1 = -4x-5
x^2 - 7x +6 =0
x1 = 1 y1 = -9
x2 = 6 y2 = -29
7) 10x+y число
x+y + 9 = 10x+y
9 = 9x
x = 1
(10x+y)^2 = 180 +y^2
100x^2 +20xy +y^2 =180 + y^2
100 +20y + y^2 = 180 + y^2
20y -80 = 0
y=4
число 14
8-е не знаю как