I need some help

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The number x is a solution to the equation 5x^2 + 4 = 3x + 9. What is the value of (10x-3)^2?

So using the quadratic formula we get

what I'm confused about is the fact that it asks for one solution and that is not possible with the plus-minus sign. Can anybody help? Thanks

$x = {3 \pm \sqrt{109} \over 10}$

Guest Feb 12, 2022

Alan · Answer 1 · 2022-02-12T12:51:36

Rearrange your solution to get 10x - 3.

As you note, there are two values $\pm\sqrt{109}$

What happens when you square these?