Help? How can I solve this form of quadratic equation?

Change it to the correct form by subtracting 3 from each side
2a^2 – a – 3 = 0
Then, one way to solve it is by factoring
(2a + 3)(a – 1) = 0
This gives a = -3/2 , 1

I tried substituting;

If a = 2, then the equation becomes 8–2 = 6

If a = !, then the equation becomes 2–2= 0.

I then saw that 3 was ½ of 6 and suddenly found what a was equal to.

Thank you. What about when you have a problem like this?(2x+3)(x-1)=25. I already foiled it out and tried to set it to 0.

@PhiNotPi sure you did that factoring correct?

Should that not be (2a-3)*(a+1)=0 ? => a = -1 or a = 1½?

No. This is how the problem is written. If only it was that simple.

Revised answer:
Change it to the correct form by subtracting 3 from each side
2a^2 – a – 3 = 0
Then, one way to solve it is by factoring
(2a – 3)(a + 1) = 0
This gives a = 3/2 , -1