Answer:
32
Explanation:
"A number decreased by 7" would be (n-7).
If 4 is mult. by this quantity, the product is 100:
(n-7)(4) = 100.
Dividing both sides by 4 clears out the fraction(s): n - 7 = 25.
Adding 7 to both sides isolates the desired answer, n:
n = 25 + 7 = 32