Question

The Quadratic Formula 7:Solving Quadratic Equations

laro
The Quadratic Formula
Text
Guided Practice
Use the quadratic formula to solve the equation. If necessary, round answers to the nearest hundredth.
8x2-3x - 7=0
A. 1.12, -0.74
B. 1.14,-0.77
C. -1.14,0.77

Answer 1

1.14, –0.77

Explanation:

I got it right in grandpoint.

Answer 2

B. 1.14, -0.77

Explanation:

As you know the quadratic formula gives you the solution to

ax² + bx + c = 0

as ...

`x=(-b\pm√(b^2-4ac))/(2a)`

Here, we have a=8, b=-3, c=-7, so the formula tells us the solution is ...

`x=(-(-3)\pm√((-3)^2-4(8)(-7)))/(2(8))=(3\pm√(233))/(16)\\\\x\approx \{-0.7665,1.1415\} \qquad\text{matches choice B}`