Solve using the quadratic formula. Leave Irrational answers in radical form.

x2 + x - 20 = 0

The solutions are

and

x1 = 4

x2 = - 5

Step-by-step explanation:

There is a formula to solve the quadratic equations, which is:

[-b + - √ (b² - 4 ac) ] / (2a)

Quadractic equations have this look:

ax² + bx + c = 0

You need to stablish the numbers:

where a, is the number with x², b the x and c, the independent term.

x² + x - 20 = 0 For this case:

a = 1; b = 1; c = - 20. We replace in the formula

[-1 + - √ (1² - 4 1 (-20)) ] / (2.1)

(-1 + √81) / 2 = 4

(-1 - √81) / 2 = - 5