185k views
0 votes
How do I solve this?

x^2 + 8x - 4 = 0

User Seibar
by
7.4k points

1 Answer

1 vote

Answer: -2(2 + sqrt(5)) and -2(2 - sqrt(5))

Explanation:

We'd want to use the quadratic formula, because there's no two numbers that add to 8 and multiply to equal -4.

Recall that the quadratic formula is:


x=(-b \pm √(b^2 - 4ac))/(2a)

Each letter corresponds to:

ax^2 + bx + c

So, if we were to put in the values corresponding into the function, it would look like:


(-8 \pm √(64 +16))/(2)

This should give us the answer of:

-2(2 + sqrt(5)) and -2(2 - sqrt(5))

User Ninikin
by
7.3k points