a is the coefficient in front of x2, , so a = 1. b is coefficient in front of the x, so here b= 4 c is the coefficient, or the term without any x next to it, so here c = -21 So, now we plug it into the quadratic formula.
Joey Helping Arianna
The quadratic formula helps you solve quadratic equations. First we need to identify the values for a, b, and c (the coefficients). First step, make sure the equation is in the format from above, ax2 + bx + c = 0 x2+4x-21=0
Arianna seems to get it, but now she needs to try it on her own.
Joey Checking the Work
Wow! Yes. This is correct. Good Job! You see. All you needed was to see the work step by step. Plus you had a great teacher *cough cough* me.
Arianna looked at her paper and noticed that she needed to first put it into the format : ax2 + bx +c = 0
2. 3x2+6x= -10
Arianna noticed that she can’t take the square root of a negative number without using imaginary numbers, so that tells us there’s no real solutions to this equation. This means that at no point will y = 0, the function won’t intercept the x-axis.
Arianna finally understood the quadratic formula. She understood when there is a solution and when there isn't, which can be tricky, but she got it. Yay!
OMG!! Yay. Thank you Joey for helping me. I really needed this.