Answer:
19
Step-by-step explanation:
12-n/7 = -1
Cross multiply
We have 12-n = -7
Collect like terms
12 + 7 = n
Therefore n = 19
Answer:
n = -5, 3.
Step-by-step explanation:
n^2 + 2n - 15 = 0
Let's check if we can factor this quadratic:
We need 2 numbers whose product is -15 and whose sum is +2.
There are 2 such numbers and they are +5 and -3, so the factors are:
(n + 5)(n - 3) = 0.
n + 5 = 0 or n - 3 = 0
therefore the zeroes are -5 and 3.
