Answer :
5f² - 3f = 8
5f² - 3f - 8 = 0
f = -(-3) +/- √((-3)² - 4(5)(-8))
2(5)
f = 3 +/- √(9 + 160)
10
f = 3 +/- √(169)
10
f = 3 +/- 13
10
f = 3 + 13 f = 3 - 13
10 10
f = 13 f = -10
10 10
f = 1.3 f = -1
5f² - 3f - 8 = 0
f = -(-3) +/- √((-3)² - 4(5)(-8))
2(5)
f = 3 +/- √(9 + 160)
10
f = 3 +/- √(169)
10
f = 3 +/- 13
10
f = 3 + 13 f = 3 - 13
10 10
f = 13 f = -10
10 10
f = 1.3 f = -1