The answer should be b=3.4
Https://www.dropbox.com/s/teq5uhme9jpwma0/Screenshot%202016-10-18%2008.24.17.png?dl=0
I have the problem written out (in the picture below) but tell me if it is unclear and I will better explain it to you!
Answer:
n = {-1, 7}
Step-by-step explanation:
8n² - 56 = 48n
Subtract 48n from both sides
8n² - 48n - 56 = 0
Divide both sides by 8
n² - 6n - 7 = 0
Factor
alternately use the quadratic equation or complete the square
(n - 7)(n + 1) = 0
n = {-1, 7}