17.0k views
3 votes
Solve for x. Write both solutions, separated by a comma. 8x^2-2x-15=0

User Ozkar
by
7.4k points

2 Answers

3 votes

Answer:Factor by grouping.

Hello!

_________________

8x^2-2x-15=0

( 4x + 5 ) (2x - 3) = 0

Explanation:

If any individual factor on the left side of the equation is equal to 0 , the entire expression will be equal to 0.

Set 4x + 5 equal to 0 and solve for x.

4x + 5 = 0

Subtract 5 from both sides of the equation.

4x = -5

Divide each term by 4 and simplify.

4x/4 = -5/4

x = -5/4

Set 2x - 3 equal to 0 and solve for x.

x = 3/2

The final solution is all the values that make ( 4x + 5) ( 2x -3) = 0 true.

x = - 5/4 , 3/2.

Hope this helped you and sorry for take so long!

User Binford
by
6.7k points
5 votes

Answer:

x₁ = -5/4 (-1.25)

x₂ = 3/2 (1.5)

Step-by-step explanation:

8x² - 2x - 15 = 0

8x² + 10x - 12x - 15 = 0

2xx(4x + 5) - 12x - 15 = 0

2xx (4x + 5) - 3(4x + 5) = 0

(4x + 5) × (2x - 3) = 0

4x + 5 = 0 → x = -5/4 (-1.25)

2x - 3 = 0 → x = 3/2 (1.5)

Hope this helps! :)

User Aldekein
by
7.3k points