Answer:
8x-3
Step-by-step explanation:
Average of 2 numbers means add the two numbers and divide by 2
(y+z)/2 = 5x
Let z = 2x+3
(y+2x+3)/2 = 5x
Multiply each side by 2
y+2x+3 = 10x
Subtract 2x from each side
y+3 = 10x-2x
y+3 = 8x
Subtract 3
y = 8x-3
The other number is 8x-3
