## ashleyb 2 years ago Solve. x^2 + x = 20

1. Izzy25

okay so first you move 20 over the = sign

2. UnkleRhaukus

$x^2+x=20$ $x^2+x-20=0$ $x=\frac{-b\pm\sqrt{b^2-4ax}}{2a}$

3. Izzy25

so it becomes this: |dw:1343183162557:dw|

4. Izzy25

and then like the guy did above you use the QUADRATIC FORMULAAA .. it's quite hectic i tell you... do you need help with that... i can walk you through it

5. ashleyb

i tried that way already but my hw is asking me to find two x's

6. Izzy25

that is it

7. ashleyb

oh..then i must of did something wrong

8. Izzy25

so you don't know how to do it because the quadratic formula DOES give u 2 answers

9. UnkleRhaukus

$a=1,\qquad b=1,\qquad c=-20$

10. Izzy25

still want me to walk you though it?

11. Izzy25

* through

12. Izzy25

or unkleR can help u that is...

13. ashleyb

|dw:1343183363230:dw|when i did the quadraric formula i got

14. Izzy25

GOODDDD

15. Izzy25

okay so now just do it one by one... your looking at 2 equations!

16. Izzy25

|dw:1343183439776:dw|

17. Izzy25

or you could leave it like that... idk what ur teacher likes best

18. ashleyb

oh okay. i understand now. thx for ur help

19. Izzy25

UR WELCOME

20. .Sam.

You can use sum of roots and product of roots, x^2-(SOR)+(POR)=0 SOR=a+b=-1 POR=ab=-20 Simultaneous equations, a=-5, b=4 Roots are x=-5, x=4