Answer:
all work is answer and shown and pictured
Answer:
9
Step-by-step explanation:
Let's say Mark is M and his brother is B.
M+5=B
M+B=23
Now we can solve using subsitution.
M+M+5=23
(Subtract 5 from both sides)
2M=18
M=9
Hope this helped!
"log" standing alone actually means "logarithm to the base 10."
Thus, y = log x <=> y = log x
10
y
Stated another way (inverse functions), x = 10