Answer:
For the expressions 4x+5+x+9 and 9x+10 to be equivalent, they must have the same value for any value of x.
So we can set the two expressions equal to each other and solve for x.
4x + 5 + x + 9 = 9x + 10
Simplifying the left side:
5x + 14 = 9x + 10
Subtracting 5x from both sides:
14 = 4x + 10
Subtracting 10 from both sides:
4 = 4x
Dividing both sides by 4:
x = 1
So the expressions 4x+5+x+9 and 9x+10 are equivalent when x = 1.