Question

[(280÷4-a)×2+100:5]:3=[(160:6+5a)×2+4×5]:3

Answer 1

$\: (70 - a) \times 2 + 20 = \\ ( \frac{80}{3} + 5a) \times 2 + 20$
$- 5a - a = 70 - \frac{80}{3}$
$- 6a = - \frac{52}{3}$
$a = - \frac{52}{3} \times - \frac{1}{6}$
$a = + \frac{52}{18}$
$a = \frac{26}{9}$