325,095 views
12 votes
12 votes
3x^2-8=5x solve using quadratic equation

User Wanbo
by
3.2k points

2 Answers

24 votes
24 votes

Answer:

x = -1 or x = 8/3

Explanation:

3x² - 8 = 5x

3x² - 5x - 8 = 0

3x² - 8x + 3x - 8 = 0

(Here you find two numbers which have a sum of -5 and a product of 3×-8= -24. These two numbers are -8 and 3. -8 + 3 = -5 and -8 × 3 = -24.)

(3x² - 8x) (3x - 8) = 0

x(3x - 8) +1(3x - 8) = 0

(x + 1) (3x - 8) = 0

x + 1 = 0 OR 3x - 8 = 0

x = -1 3x = 8

x =
(8)/(3)

User Aikhs
by
3.2k points
11 votes
11 votes
The answer is -1 because x=8/3 and x also =-1
User Mvand
by
2.6k points