Factor the expression by using the GCF: \[ 45 z+50 \]

Step 1 ：Identify the greatest common factor (GCF) of 45 and 50. The GCF is the largest number that divides both numbers without leaving a remainder. In this case, the GCF of 45 and 50 is 5.

Step 2 ：Factor the expression \(45z + 50\) by dividing each term by the GCF. This gives us the factored expression \(5(9z + 10)\).

Step 3 ：Final Answer: The factored expression is \(\boxed{5(9z + 10)}\).