Đáp án:
a) 69 ; b) 28 ; c) 15 ; d) 16 ; e) 35 ; f) 1 ; g) 8 ; h) 4 ; i) 2624 ; g) 2
Giải thích các bước giải:
a) 2.(x - 51) = 2.2³ + 20
= 2.(x - 51) = 16 + 20
= 2.(x - 51) = 36
= x - 51 = 36 : 2
= x - 51 = 18
= x = 18 + 51
= x = 69
b) 450 : (x - 19) = 50
= x - 19 = 450 : 50
= x - 19 = 9
= x = 19 + 9
= x = 28
c) 4.(x - 3) = 7² - $1^{10}$
= 4.(x - 3) = 7² - 1
= 4x - 12 = 49 - 1
= 4x - 12 = 48
= 4x = 48 + 12
= 4x = 60
= x = 60 : 4
= x = 15
d) 135 - 5(x + 4) = 35
= 5(x + 4) = 135 - 35
= 5(x + 4) = 100
= 5x + 20 = 100
= 5x = 100 - 20
= 5x =80
= x = 80 : 5
= x = 16
e) 25 + 3(x - 8) = 106
= 3(x - 8) = 106 - 25
= 3(x - 8) = 81
= 3x - 24 = 81
= 3x = 81 + 24
= 3x = 105
= x = 105 : 3
= x = 35
f) 3².(x + 4) - 5² = 5.2²
= 3².(x + 4) - 5² = 20
= 9.(x + 4) - 25 = 20
= 9.(x + 4) = 20 + 25
= 9.(x + 4) = 45
= 9x + 36 = 45
= 9x = 45 - 36
= 9x = 9
= x = 9 : 9
= x = 1
g) (2x - 15) : 13 + 51 = 8²
= (2x - 15) : 13 + 51 = 64
= (2x - 15) : 13 = 64 - 51
= (2x - 15) : 13 = 13
= 2x - 15 = 13 : 13
= 2x - 15 = 1
= 2x = 1 + 15
= 2x = 16
= x = 16 : 2
= x = 8
h) x² : 4+ 5555 : 5³ = 29
= x² : 4 + 3125 : 125 = 29
= x² : 4 + 25 = 29
= x² : 4 = 29 - 25
= x² : 4 = 4
= x² = 4.4
= x² = 16
= x = 4 (vì 4.4 = 16)
i) $2012^{9}$.(x - 612) = $2012^{10}$
= x - 612 = $2012^{10}$ : $2012^{9}$
= x - 612 = 2012
= x = 2012 + 612
= x = 2624
k) 71 + (26 - 3x) : 5 = 75
= (26 - 3x) : 5 = 75 - 71
= (26 - 3x) : 5 = 4
= 26 - 3x = 4.5
= 26 - 3x = 20
= 3x = 26 - 20
= 3x = 6
= x = 6 : 3
= x = 2
