Math Problem Solver

Assuming $B$ and $b$ are referring to the same variable.

Assuming $A$ and $a$ are referring to the same variable.

The system of linear equations has exactly one solution.

The substitutions are $a = 20$, $b = 5$.

$$A + B + C = C + 25$$

Solve $a + b = 25$ for $a$. $$a = 25 - b$$

Substitute $25 - b$ for $a$ in $a - b = 15$ and simplify. $$\begin{aligned}a - b &= 15 \\ \left(25 - b\right) - b &= 15 \\ b &= 5 \end{aligned}$$

Use substitution of the numerical value of $b$ to get the values of $a$. $$\begin{aligned}a &= 25 - b \\ a &= 25 - 5 \\ a &= 20\end{aligned}$$

By substituting these values into the expression, we find that:$$\begin{aligned} A + B + C &= C + 5 + 20\\ &=C + 25\end{aligned}$$