I'll do one, and you try the other.
2x^2+7x = 4
(x^2 + 7/2 x) = 2
(x^2 + 7/2 x + (7/4)^2) = 2 + (7/4)^2
(x + 7/4)^2 = 81/16
x + 7/4 = ±9/4
x = -7/4 ± 9/4
x = -4 or 1/2
Just recall that (x+a)^2 = x^2 + 2ax + a^2
That's why I added (7/4)^2 to both sides.
The second one has a typo, so fix it and follow the same logic.
Can you solve these equation by completing the square
2x^2+7x-4=0
3x^2x-1=0
1 answer
3 answers