A, 5.(x-9)=350 C,11( x-9)=77 E, 2(x-51)=2.2 mũ 3+20 B,2x-49=5.3 ³ D,200 -(2x+6)= 4 ³

Đáp án:

 $A 5(x-9) =350$

$⇔ x-9 = 350 : 5$

$⇔x-9 = 70$

$⇔x = 70 + 9$

$⇔x=79$

Vậy $x=79$

$C , 11(x-9) = 77$

$⇔x-9 = 77 : 11$

$⇔x-9 = 7$

$⇔x=7 + 9$

$⇔x=16$

Vậy $x=16$

$E, 2(x-51) = 2 . 2³ +20$

$⇔ 2(x-51) = 2 .8 +20$

$⇔2(x-51) = 16 +20$

$⇔2(x-51) = 36$

$⇔x-51 = 36 : 2$

$⇔x-51 = 18$

$⇔x=18 + 51$

$⇔x=69$

Vậy $x=69$

$B, 2x-49 = 5 . 3³$

$⇔ 2x-49 = 5 . 27$

$⇔2x-49 = 135$

$⇔2x=135 + 49$

$⇔2x = 184$

$⇔x= 184 : 2$

$⇔x=92$

Vậy $x=92$

$D, 200 – (2x-6) = 4³$

$⇔ 200-(2x-6) =64$

$⇔ 2x-6 = 200 -64$

$⇔2x-6 = 136$

$⇔2x=136+6$

$⇔2x=142$

$⇔x=142 : 2$

$⇔x=71$

Vậy $x=71$

 

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