Question

HELP ME ASAP!!! solve by graphing
5x^2+20x+15=0

Answer 1

A

Answer 2

B

Answer 3

C

Answer 4

D

Answer 5

since the number in front of x^2 in 5x^2+20x+15=0 is positive, the graph will open upwards... so you can eliminate the graph that opens down.

You can also divide both sides of 5x^2+20x+15=0 by 5 to make it easier to solve.

Answer 6

(divide *everything* by 5)

Answer 7

so wait were solving the equation by x right ?

Answer 8

Yes, solving it for x. But you can divide it by 5 first, then we'll solve it.

Answer 9

so it would be x^2+20x+15=5 ?

Answer 10

You need to divide every term of 5x^2+20x+15=0 by 5. Every term, everything.

Answer 11

\[\Large \frac{ 5x^2+20x+15 }{ 5 }=\frac{ 0 }{5}\]

Answer 12

oh okay

Answer 13

so its x^2+4x+3=5

Answer 14

Correct on the left side. What's 0/5? What's 0 divided by anything?

Answer 15

It's not 5...

Answer 16

oh haha my bad

Answer 17

okay so it would be x^2+4x+3=0
and then do you just + 3 on both sides ?

Answer 18

No leave everything where it is, now try to factor it.

Answer 19

how would you do that ? :P

Answer 20

Find two numbers that multiply to the last number, 3, and add up to 4

Answer 21

3*1 is 3 and 3+1 is 4

Answer 22

Yep now put them into your (x+3)(x+4) and so find which graph has zeroes -3 and -4

Answer 23

so it would be D ?

Answer 24

Oh, yes sorry, (x+3)(x+1) not what i wrote above, you're correct about D :)

Answer 25

okay thank you :)