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Question

How can I solve 2x²-3=15

Answer 1

Hello, thank you for taking the time to post your question!

The key on this type of question is that you are trying to get the “x” variable by itself … so I would start by combining like terms to get

2x^2 – 3 = 15

2x^2 = 18

Then you can solve for x algebraically by dividing both sides by 2 and taking the square root

x^2 = 9

x = -3 or x = +3

I hope that helps get you moving in a better direction on this type of question! Feel free to reach out if you have any additional questions beyond that :)

Answer 2

Isolate the x term onto one side of the equation, divide both sides by the constant of the x term, and take the square root of both sides.

 

2x² - 3 = 15

2x² = 18

x² = 9 

x = 3 or x = -3

 

Note that the square root of 9 is 3 or -3, both are solutions.

(-3)² = -3*-3= 9