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!
After 25 days. 300=triple 100+8x=300. is that 20 words?
Answer:
y = 7x - 4
just as it says in words
Answer:
(x, y) = (8, -2)
Step-by-step explanation:
Substitute:
3(-4y) + 2y = 20
-12y + 2y = 20
-10y = 20
y = -2
x = -4(-2) = 8