Tìm số tự nhiên x , biết:

- Hướng dẫn giải

a, 36:(x–5) = $2^2$

(x–5) = 9

x = 14

b, [3.(70–x)+5]:2 = 46

[3.(70–x)+5] = 92

70–x = 29

x = 41

c, 450:[41–(2x–5)] = $3^2$.5

41–(2x–5) = 10

2x–5 = 31

2x = 36

x = 18

d, 230+[$2^4$+(x–5)] = 315.${2018}^0$

16+(x–5) = 315–230

x–5 = 85–16

x = 69+5

x = 74

e, $2^x+2^{x+1}$ = 48

$2^x$.(2+1) = 48

$2^x$ = 16 = $2^4$

x = 4

f, $3^{x+2}+3^x$ = 2430

$3^x.\left(3^2+1\right)$ = 2430

$3^x$ = 2430:10 = 243 = $3^5$

x = 5