Bài toán 4 : Tìm x, biêt.
a. 5x – 16 = 40 + x
b. 4x – 10 = 15 – x
c. -12 + x = 5x – 20
d. 7x – 4 = 20 + 3x
e. 5x – 7 = – 21 – 2x
f. x + 15 = 7 – 6x
g. 17 – x = 7 – 6x
h. 3x + (-21) = 12 – 8x
k. 125 : (3x – 13) = 25
l. 541 + (218 – x) = 735
m. 3(2x + 1) – 19 = 14
n. 175 – 5(x + 3) = 85
o. 4x – 40 = |-4| + 12
p. x + 15 = 20 – 4x
q. 8x + |-3| = -4x + 39
r . 6(x – 2) + (-2) = 20 – 4x
- dfhj mình cũng đang vắt hết cả óc ra để nghĩ đây
a) 5x - 16 = 40 + x
5x -x = 40 +16
4x = 56
x = 56 : 4
x = 14
b, 4x - 10 = 15 - x
4x + x = 15 +10
4x + x = 25
5x = 25
x = 25 : 5
x = 5
c, -12 + x = 5x - 20
x - 5x = -20 + 12
-4x = -8
x = -8 : (-4)
x = 2
d, 7x - 4 = 20 + 3x
7x - 3x = 20 + 4
4x = 24
x = 6
x = 7 : (-13)
x = \(\dfrac{-7}{13}\)
g, 17 - x = 7 - 6x
-x + 6x = 7 - 17
5x = -10
x = -10 : 5
x = -2
h, 3x + (-21) = 12 - 8x
3x - 21 = 12 - 8x
3x + 8x = 12 + 21
11x = 33
x = 33 : 11
x = 3
e, 5x - 7 = -21 -2x
5x + 2x = -21 + 7
7x = -14
x = -14 : 7
x = -2
f, x + 15 = 7 - 6x
x + 6x = 7 - 15
7x = -8
x= \(-\dfrac{8}{7}\)
m, 3(2x + 1) - 19 = 14
3(2x + 1) = 14 + 19
2x + 1 = 33 : 3
2x + 1 = 11
2x = 11 - 1
x = 10 : 2
x = 5
n, 175 - 5(x + 3) = 85
5(x + 3) = 175 - 85
x + 3 = 90 : 5
x = 18 - 3
x = 15
k,125 : (3x - 13 ) = 25
3x - 13 = 125 : 25
3x - 13 = 5
3x = 13 +5
3x = 18
x = 18 : 3
x = 6
I,541 + ( 218 - x ) = 735
218 - x = 735 - 541
218 - x = 194
x = 218 - 194
x= 24
o, 4x - 40 = |-4| + 12
4x - 40 = 4 + 12
4x = 16 + 40
4x = 56
x = 56 : 4
x = 14
p, x + 15 = 20 - 4x
x + 4x = 20 - 15
5x = 5
x = 5 : 5
x = 1
q. 8x + \(|\)-3\(|\) = -4x + 39
8x +4x + 3 = 39
12x = 36
x = 36 : 12
x = 3
r, 6.(x - 2 ) + (-2)= 20 - 4x
6x - 12 + (-2) = 20-4x
6x + 4x = 20 +12 +2
10x = 34
x = 34 : 10
x = 3,4
