Question

If $13y+25=64$, what is the value of $4y-7$?

Short answer

The required value is 5.

Step-by-step solution

Step 1. Isolate the variable.

$\begin{array}{l}13y+25=64\\ 13y=64-25\\ 13y=39\end{array}$

Step 2. Solve for y.

$\begin{array}{l}y=\frac{39}{13}\\ y=3\end{array}$

Hence, the value of $y=3$.

Step 3. Put the value of y into the given expression.

Put $y=3$into $4y-7$.

$\begin{array}{c}4\left(3\right)-7=12-7\\ =5\end{array}$

The value of the expression is 5.