x/4=y/9 và 2x+3y=20

(3x+2) mũ 2 = (7-2x) mũ x

(x+5) mũ 3 = 216

(3x+2) mũ 2=(7-2x) mũ x

-1/1*2-1/2*3-1/3*4-...-1/2020*201

-4/1*5-4/5*9-4/9*13-...-4/(n-4)

15/6+14/35-20/9-15/25

5/7-(6/5-9/7)

(-3/4+5/12)-(-5/4)

3/2+x=3/2-7

-21/5-x=9/4

-x-4/9=-2/27

(3,25-2/5*x)/-7/4=-3

9/2/(5/2-15/4)+1/4

75%-3/2*4/3+1,5/(-9/4)-1/4

(1-1/5-2/3)/(12/5+1/3)

tính giá trị biểu thức 11/9*15/4-11/4*7/9-11/9*5/4