Đáp án + Giải thích các bước giải:
$\text{6x + x = 28}$
$\text{⇔ x.(6 + 1) = 28}$
$\text{⇔ 7.x = 28}$
$\text{⇔ x = 4}$
$\text{5x + 3x = 60}$
$\text{⇔ x.(5 + 3) = 60}$
$\text{⇔ 8x = 60}$
$\text{⇔ x = $\dfrac{60}{8}$ = $\dfrac{15}{2}$ }$
$\text{7x - 2x = 40}$
$\text{⇔ x(7 - 2) = 40}$
$\text{⇔ 5x = 40}$
$\text{⇔ x = 8}$
$\text{$2^{x}$ : $2^{5}$ = 1}$
$\text{⇔ $2^{x - 5}$ = $2^{0}$ }$
$\text{⇔ x - 5 = 0}$
$\text{⇔ x = 5}$