# How do you evaluate a-2y when a=-2/3 and y=4/5?

Mar 5, 2018

You will get the answer $- \frac{34}{15}$

#### Explanation:

Evaluating something is basically substituting a value in for a variable. They give you value -2/3 for a, and they give you 4/5 for y. So when we sub those in we get the equation

$- \frac{2}{3} - 2 \left(\frac{4}{5}\right)$

So this looks pretty easy to solve. From here, if we use PEMDAS we see that we must multiply to by the fraction first and we get

$- \frac{2}{3} - \frac{8}{5}$

Since we can't subtract without like denominators we want to find the lowest common denominator, which in this case will be 15. Now we have our new fractions

$- \frac{10}{15} - \frac{24}{15}$

So if we subtract the two numerators we get -34

$- \frac{34}{15}$

And this fraction can't be simplified so it is our final answer. Hope this helps!