# How do you solve (2a+4)/3=6/9?

Jul 14, 2016

$a = - 1$

#### Explanation:

Solve by cross multiplication ($\frac{a}{b} = \frac{c}{d}$ = $a d = b c$).

$\frac{2 a + 4}{3} = \frac{6}{9}$

$\left(2 a + 4\right) \left(9\right) = \left(3\right) \left(6\right)$

$18 a + 36 = 18$

$18 a = - 18$

$a = - 1$

Plug in $- 1$ for $a$ to check.

$\frac{2 \left(- 1\right) + 4}{3} = \frac{6}{9}$

$\frac{2}{3} = \frac{6}{9}$

$\frac{2}{3} = \frac{6 \div i \mathrm{de} 3}{9 \div i \mathrm{de} 3}$

$\frac{2}{3} = \frac{2}{3}$