Question

Решите и распишите уравнение:
9m+8m(5-2m)=9m^2-(5m+7)(5m-7)
4x(x-1)-8=(1+2x)(2x-1)-6x
-5y+(3y+4)(3y-4)=(4y-3)(3+4y)-7y^2

Answer 1

$9m+8m(5-2m)=9m^2-(5m+7)(5m-7)\\ 9m+40m-16m^2=9m^2-(25m^2-49)\\ -16m^2+49m=-16m^2+49\\ -16m^2+49m+16m^2=49\\ 49m=49\\ m=1$


$4x(x-1)-8=(1+2x)(2x-1)-6x\\ 4x^2-4x-8=4x^2-1-6x\\ 4x^2-4x^2-4x+6x=8-1\\ 2x=7\\ x= \frac{2}{7}$


$-5y+(3y+4)(3y-4)=(4y-3)(3+4y)-7y^2\\ -5y+9y^2-16=16y^2-9-7y\\ 9y^2-9y^2-5y=7\\ -5y=7\\ y=- \frac{7}{5}$

Answer 2

9m+8m(5-2m)=9m^2-(5m+7)(5m-7)
9m+40m-16m^2=9m^2-(25m^2-49)
-16m^2+49m=9m^2-25m^2+49
-16m^2-9m^2+25m^2+49m=49
49m=49
m=1
ответ: 1

4x(x-1)-8=(1+2x)(2x-1)-6x
4x^2-4x-8=2x-1+4x^2-2x-6x
4x^2-4x-8=4x^2-6x-1
4x^2-4x-4x^2+6x=-1+8
2x=7
x=3,5
ответ: 3,5

-5y+(3y+4)(3y-4)=(4y-3)(3+4y)-7y^2
-5y+9y^2-16=16y^2-9-7y^2
-5y+9y^2-16=9y^2-9
-5y+9y^2-9y^2=-9+16
-5y=7
y=-7/5
y=-1,4
ответ: -1,4