Решение:
2x+2+3x-9=5x-7
2x+3x-5x=9-7-2
0=0
Ответ: х-любое число, x∈R
(2x+3)/(x²+x-12)-1/2≤0
(4x+6-x²-x+12)/(x²+x-12)≤0
(-x²+3x+18)/(x²+x-12)≤0
(x²-3x-18)/(x²+x-12)≤0
(x-6)(x+3)/(x+4)(x-3)≤0
x=6 x=-3 x=-4 x=3
+ _ + _ +
------(-4)--------[-3]---------(3)--------[6]-------
x∈(-4;-3] U (3;6]
2c + 7c^2 = 2c (1 + 3.5c)
3(a+2)+b(a+2)=(a+2)(3+b); 4f(5m-3n)-5k(5m-3n)=(5m-3n)(4f-5k); 5m(a-3b)+(a-3b)=(a-3b)(5m+1); 5m(a-3b)-a+3b=5m(a-3b)-(a-3b)=(a-3b)(5m-1).