# How do you solve and check your solutions to -21=-3/5t?

Apr 15, 2017

$t = 35$

#### Explanation:

Our main goal here is to make $t$ stand alone

We can start by writing what is on the left hand side as a fraction.

$\frac{- 21}{1} = - \frac{3}{5} t$

Now let's cross product or cross multiply to get rid of the fractions

$- 21 \times 5 = 1 \times - 3 t$

Simplify

$- 105 = - 3 t$

Divide both sides by $- 3$

(cancel(-)105)/(cancel(-)3)=(cancel(-3)t)/(cancel(-3)

$t = \frac{105}{3} = \frac{\cancel{3} \times 35}{\cancel{3}}$

$\Rightarrow t = 35$

To check, you simply substitute $t = 35$ into the original equation.

$- 21 = - \frac{3}{5} t , t = 35$

$- 21 = - \frac{3}{5} \times 35$

$- 21 = - \frac{105}{5}$

Cross product

$- 21 \times 5 = - 105$

$- 105 = - 105$

BAM!