# How do you check a linear equation and find if 7 is a solution to 5x-5=30?

##### 1 Answer
Feb 5, 2015

In general, to evaluate any function $f \left(x\right)$ in a specific point, you simply need to substitute every $x$ with that specific value.

In your case, rather than evaluating a function, you want to check an identity. The spirit is the same, you only need to substitue $x \setminus \rightarrow 7$, and see if you obtain a true statement, or a false one.

Substituting, we have
$5 x - 5 = 30 \setminus \rightarrow 5 \setminus \cdot 7 - 5 = 30 \setminus \iff 35 - 5 = 30 \setminus \iff 30 = 30$
which is of course true.