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222-9+11+12:2*14+14 = ? ( )

## Toán Lớp 6: a/ 89 – (73 – x) = 20 b/ x – 36 : 18 = 12 + 15 c/ 16. 4^x = 4⁸ d/ 8.x + 20 = 76

Toán Lớp 6: a/ 89 – (73 – x) = 20
b/ x – 36 : 18 = 12 + 15
c/ 16. 4^x = 4⁸
d/ 8.x + 20 = 76

1. $a) 89 – ( 73 – x ) = 20$
$73 – x = 89 – 20 = 69$
$x = 73 – 69 = 4$
$b) x – 36 : 18 = 12 + 15 = 27$
$x – 2 = 27$
$x = 27 + 2 = 29$
$c) 16 . 4^x = 4^8$
$4^2 . 4^x = 4^8$
$4^{2+x} = 4^8$
$⇒ 2 + x = 8$
$x = 8 – 2 = 6$
$d) 8x + 20 = 76$
$8x = 76 – 20 = 56$
$x = 56 : 8 = 7$

2. $\text{a/ 89 – (73 – x) = 20}$ $\\$ $\text{73 – x = 89 – 20}$ $\\$ $\text{73 – x = 69}$ $\\$ $\text{x = 73 – 69}$ $\\$ $\text{x = 4}$ $\\$ $\text{b/ x – 36 : 18 = 12 + 15 }$ $\\$ $\text{x – 2 = 27}$ $\\$ $\text{x = 27 + 2}$ $\\$ $\text{x = 29}$ $\\$ $\text{c/ 16.$4^{x}$=$4^{8}$}$ $\\$ $\text{$4^{2}4^{x}$=$4^{8}$}$ $\\$ $\text{$4^{2 + x}$=$4^{8}$}$ $\\$ $\text{2 + x = 8}$ $\\$ $\text{x = 8 – 2}$ $\\$ $\text{x = 6}$ $\\$ $\text{d/ 8.x + 20 = 76}$ $\\$ $\text{8x = 76 – 20}$ $\\$ $\text{8x = 56}$ $\\$ $\text{x = 56 : 8}$ $\\$ $\text{x = 7}$