=>5/2x-4/7=-4/7
=>5/2x=0
=>x=0
=>5/2x-4/7=-4/7
=>5/2x=0
=>x=0
-1/21+-1/28
-8/18+-15/27
x-2/5=5/7
4/5-7/10+2/7
2/3+7/4+1/2+3/8
a,5^x+4-3×5^x+3=2×5^11
b,3×5^x+2+4×5^x-3=19×5^10
c,6×8^x-1+8^x-1=6×8^19+8^21
d,5×2^x+3×2^x+2=5×2^5+3×2^7
Bài 1 thực hiện phép tính
a ) 8/15 . 7/13 +8/15 . 6/13
b ) 3/4 + -7/12 - 2/3
Bài 2 Tìm x biết
x /2, 7= -2/3, 6
Bài 3 tìm x , y biết
x/2 = y/5 và x + y = -21
3x-21/3 + 4x-32/2 = 5x-37/4 + 9x-33/6
x+5/4 + x+6/3 + x+7/2 + x+8/1 = -4
Bài 1 tìm số hữu tỉ x biết
a) x*(-3/7)=4/21
b) (-4/7):x=2/5
c) x+1/12= -3/8
d) 2/15-x=-3/10
e) -x+4/5=1/2
f) 3/4(x+1)-1/2=3/7
g) -3/2-2x+3/4=-2
h) -x+4/5=1/2
tính
a. -3/4 x 12/-5 x (-25/6)
b. -2 x -38/21 x -7/4 x (-3/8)
c. (11/12: 33/16) x 3/5
d. 7/23 x [(-8/6)- 45/18]
Bài 1:
a,11/125-17/18-5/7+4/9+17/14
b,(7+7/5-2/3)-(4+4/5+3/8)+(3-3/5+2/3+3/8)
c,-13/25.5/32.23/-13.(-64)
Bài 2:
a,11/13-(3/42-x)=-(13/28-11/13)
b,x2/3x+5/7=3/10
c,x-21/13x+1/3=-2/3
Tính:
a) -5/7(14/5 - 7/10) : |-2/3| - 3/4(8/9 + 16/3) + 10/3(1/3 + 1/5)
b) 17/-26(1/6 - 5/3) : 17/13 - 20/3(2/5 - 1/4) + 2/3(6/5 - 9/2)
c) -8/9(9/8 - 3/2) + 5/4 : (5/2 - 15/4) - 3/4(10/9 - 8/3) : (-1/3)
d) 21/10 : (12/5 - 9/10) . (-4/7) - 3/2(1/6 - 7/12) + 1/5(3/2 - 1/4)
Tìm x
A)2x-3/4=-5/8
B)3x-1/7=1:14-1/21
C)-2/5.x+1/4=1+1/3
D)1:6.2x-3=1/2.(-x+1/4)-2/3
\(b) 5^{x+4} - 3 . 5^{x+3} = 2. 5^{11} \)
\(c) 2 . 3^{x+2} + 4 . 3^{x+1} = 10 . 3 ^{6}\)
\(d) 6 . 8 ^ {x-1} + 8 ^ {x+1} = 6 . 8^ {19} + 8 ^ {21}\)