Question

Use the quadratic formula to solve xsquared + 3x-4 = 0, and then verify your answer by graphing.

a.x= -41 b.4.1
C. X = -4,- 1
d. x= -4,2

I need help please ​

Answer 1

at answer C, that's supposed to be x= -4 , 1 and that's the answer.

Answer 2

x^2 + 3x - 4 = 0

Quadratic formula:

x = -b +- sqrt{b^2 - 4ac}/(2a)

Let a = 1

Let b = 3

Let c = -4

Just plug into the quadratic formula and do the math.

We are looking for x.

x = -3 +- sqrt{3^2 - 4(1)(-4)}/2(1)

x = -3 +- sqrt{9 + 16}/2

x = -3 +- sqrt{25}/2

x = (-3 +- 5)/2

Separate x into two parts.

Part 1

x = (-3 -5)/2

x = (-8)/2

x = -4

Part 2

x = (-3 + 5)/2

x = 2/2

x = 1

Answer: x = -4, x = 1