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

1 Answer
KillerBunny
Feb 5, 2015

In general, to evaluate any function f(x) 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 \rightarrow 7, and see if you obtain a true statement, or a false one.

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

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