(2x-39).7+3=80
(2x-39).7=80-3
(2x-39).7=77
2x-39=77:7
2x-39=11
2x=11+39
2x=50
x=50:2
x=25
(2x-39).7+3=80
(2x-39).7 =80-3
(2x-39).7 =77
2x-39 =77:7
2x-39 =11
2x =11+39
2x =50
x =50:2
x =25
Vậy x = 25.
Tính biết
B=7/8+7/24+7/48+7/80+..+7/10200
C=(1-1/2).(1-1/3).(1-1/4)......(1-1/100)
D=1/3+1/3mũ2+1/3mũ3+..+1/3mũ8
rut gon
a,3x(2x-7)-3x(4x-5)
b,(-7x+8)(-2x+3)-7x(2x-4)
c,(2x-3)(3x2-2x+4)-(2x-3)(3x+4)
d,(-2+7)(3x-6)-(4x-5)(2x-6)
2x+(5x+39)=25
53x.57=52020-52018
Giúp mình voi
(2x + 5) .| - 7| = 7^3
BT: Cho dãy số: 1; -3; 5; -7; 9; -11 ; 13; -15; 17; -19.
Tìm 5 số, sao cho đặt dấu ''+'' hoặc ''-'' nối các số đó với nhau đc kết quả là [15]
tim x
a, ( 3-2x ) . ( 1/3 - 1/2 ) ^2 + 4 . (7-5x ) = 9-2x
b, 7 - 3x 1 - 3x
_______ = ______
4 + x x - 5
TÌM X
a, 3 ( x + 2) - 7 ( 2x -1 ) = x - 5 ( 1 + x)
b, ( 2x - 1 ) - 3( 1 - 2x ) x - 8
\(\frac{12}{16}=\frac{-x}{4}=\frac{21}{y}=\frac{z}{80}\) \((-0,6x-\frac{1}{2}).\frac{3}{4}-\left(-1\right)=\frac{1}{3}\)
\(\frac{1}{3}x+\frac{2}{5}\left(x-1\right)=0\)
\(\left(2x-3\right).\left(6-2x\right)=0\)
\(\frac{-2}{3}-\frac{1}{3}\left(2x-5\right)=\frac{3}{2}\)
\(2|\frac{1}{2}x-\frac{1}{3}|-\frac{3}{2}=\frac{1}{4}\)
\(\frac{3}{4}-2|2x-\frac{2}{3}|=2\)
A. -15(x + 2) + 7(2x - 3)= -50
B. 3(x + 2) - 6(x - 5)= 2(5 - 2x)