Question

FAN AND MEDAL!

How do you solve -x^2+5x+6=0 ?

Answer 1

@warpedkitten @Empty @enchanted_bubbles @RedNeckOutLaw @Teddyiswatshecallsme @yomamabf @uybuyvf @ikram002p @imqwerty @OregonDuck @phi @abb0t @sammixboo @DullJackel09 @futureboy1 @GeniousCreation @Hero @jagr2713 @KAKES1967 @Loser66 @zmudz

Answer 2

plz help

Answer 3

quadratic formula should do the trick, or you could factor into \(-(x-6)(x+1)\) and solve for x that way

Answer 4

@zmudz i did this but its wrong
-x^2+5x+6=0
(-x^2-x)+(6x+6)=0
-x(x+1)+6(x+1)=0
(-x+6)(x+1)=0
-x+6=0
-x=-6
x=6
x+1=0
x=-1

Answer 5

Ah, double check your math for when you solved x=-1

Answer 6

no they are both wrong i used a graphing calculator and the zeroes are x=0 and x=-1.2

Answer 7

it wants me to solve this system algebraically

Answer 8

Lol your answers x=6 and x=1 are both correct.

Answer 9

@phi i don't know what i did wrong in solving this

Answer 10

If they want you to solve it algebraically, then why did you use a graphing calculator? :D

Answer 11

I would first multiply both sides and all terms by -1
(because I don't like -x^2)
what do you get ?

Answer 12

because the second part is for me to graph it to prove my answers

Answer 13

x^2-5x-6=0 @phi

Answer 14

now try factoring it

Answer 15

How I wish we were allowed to use a graphing calculator when we graph something. Do you know how to plot points like this?

Answer 16

but it looks like you did it correctly up top
x= 6 and x=-1

Answer 17

(x^2-2x)-(3x-6)=0
x(x-2)-3(x-2)=0
(x-3)(x-2)=0
x=3 and x=2

Answer 18

wait i messed up on the sign there

Answer 19

ok I'm confused @phi

Answer 20

This is if you graph it

Answer 21

(x^2 -6x) + (x-6) = 0

Answer 22

ok, so
\[ x^2 = 5x+6 \\ x^2 -5x-6=0\\ (x-6)(x+1)= 0 \\ x= 6 ; x= -1 \]

y= 5x+6 so at x= -1, y= 1
at x= 6 , y= 36

here is the graph with the first solution showing

Answer 23

the solution is where the two curves cross (intersect)

it is true when we are given a single curve (or line), we are often interested in where it crosses the x-axis (the x value is called the zero)
but not in this case.

Answer 24

and thats all?

Answer 25

solving two equations is the same as asking "what point lies on both curves"

Answer 26

there are two solutions
-1,1
and (6,36)

Answer 27

ok thank you!

Answer 28

you had the right idea except for the final step...
once you found x= -1 or x=6
you find the y value (using either equation)
and the (x,y) pairs are where the two curves intersect. i.e. are the "solutions"

Answer 29

oh ok thank you i have to go :)