Question

Упражнение 267 Макарычев

Answer 1

1) (6-x)(x+6)-(x-11)x=36
36-x^2-x^2+11x=36
-2x^2+11x=0
2x^2-11x=0
2x(x-5.5)=0
x1=0     x2=5.5
2) (1-3y)/11 - (3-y)/5=0
(5(1-3y)-11(3-y))/55=0
5(1-3y)-11(3-y)=0
5-15y-33+11y=0
-4y=28
y=-7

3) 9x^2 - ((12x-11)(3x+8))/4=1
(36x^2-(12x-11)(3x+8))/4 - 1 =0
(36x^2-(12x-11)(3x+8)-4)/4=0
36x^2-(12x-11)(3x+8)-4=0
36x^2-(36x^2+96x-33x-88)-4=0
36x^2-36x^2-96x+33x+88-4=0
-63x+84=0
x=-84/-63
x=1.3

4) (y+1)^2/12 - 1-y^2/24=4
(y+1)^2/12 - 1-y^2/24 - 4=0
(2(y+1)^2 - (1-y^2) - 96)24=0
2(y^2+2y+1)-(1-y^2)-96=0
2y^2+4y+2-1+y^2-96=0
3y^2+4y-95=0
D=16+4*3*(-95)=1156
x1=5
x2=-19/3