Question

Solve for x.
2x² + 4x-1=0
Enter your answers in the boxes.
X =
or x =

Answer 1

Answer: -2 ±√6
2

Explanation:
Use the quadratic formula - its better to separate it into two parts
Δ = b²-4ac
= 4² -4(2*-1)
= 16 + 8

∴ Δ = 24
Then
x = (-b ± √Δ) ÷ 2a
= (-4 ± √24) ÷ 4
= (-4 ± 2√6) ÷ 4 (simplify the surd form)
∴ x = -2 ±√6 (simplify by crossing out the 2's)
2

Answer 2

1- use de quadratic formula
2- calculate
3- simplify
4- separate solutions