Question

aflați numărul a din egalitatea:
72-{3a+[2a:3+12):6+24]:3}:2=13




dau coroana

Answer 1

Răspuns: $\red{\bf\underline{ a= 36}}$

Explicație pas cu pas:

Metoda mersului invers

$\bf 72-\big\{3a+\big[\big(2a:3+12\big):6+24\big]:3\big\}:2=13~~~\bigg|\cdot2$  

$\bf 72\cdot 2-\big\{3a+\big[\big(2a:3+12\big):6+24\big]:3\big\}=13\cdot2$

$\bf 144-\big\{3a+\big[\big(2a:3+12\big):6+24\big]:3\big\}=26$

$\bf 144=26+\big\{3a+\big[\big(2a:3+12\big):6+24\big]:3\big\}$

$\bf 144-26=\big\{3a+\big[\big(2a:3+12\big):6+24\big]:3\big\}$

$\bf 118=3a+\big[\big(2a:3+12\big):6+24\big]:3$

$\bf 118\cdot 3=9a+\big[\big(2a:3+12\big):6+24\big]$

$\bf 354=9a+\big[\big(2a:3+12\big):6+24\big]$

$\bf 354-9a=\big[\big(2a:3+12\big):6+24\big]$

$\bf 354-9a-24=\big(2a:3+12\big):6$

$\bf 330-9a=\big(2a:3+12\big):6~~~~\bigg|\cdot6$

$\bf 6\cdot\big(330-9a\big)=\big(2a:3+12\big)$

$\bf 1980-54a=2a:3+12$

$\bf 1980-54a-12=2a:3$

$\bf 1968-54a=2a:3~~~~\bigg|\cdot3$

$\bf 3\cdot\big(1968-54a\big)=2a$

$\bf 5904-162a=2a$

$\bf 5904=2a+162a$

$\bf 5904=164a$

$\bf a= 5904:164$

$\red{\bf\underline{ a= 36}}$

==pav38==

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