Question

The sum of two numbers = - 4 . The product of those two numbers is - 21. What are the two numbers?

Answer 1

Welcome to OpenStudy math
Do you have a guess of what the equation will look like or
do you want to do it trial by error?

Answer 2

I dont understand on how to figure it out best. I could do it but id be here for hours

Answer 3

So i was hoping you could maybe walk me through it?

Answer 4

Okay, I don't know how to do it at this moment either...

First I choose a variable. Let's say x & y (since we're dealing with two different #s
Try to put the variables equal to -4

Second make another equation (separate) with the same variables except equaling -21

Answer 5

(btw I'm taking the equation route)

Answer 6

So like

4: 4 8 12 16 20 24 28 32 etc
21: 21 42 63 84 etc

Answer 7

The product of the two numbers is -21 so you need to list the factors: +/- 1, 3, 7, and 21. Out of those only +/- 3 and 7 can add up to -4. Because it's a negative it has to be -7 and 3.

Answer 8

Here what adamaero is doing is great, let me help a little bit in writing it out:

So we have two numbers that add to -4 and multiply together to be -21 and we can call those numbers x and y. If we make two equations we have: \[\Large x+y = -4 \\ \Large x*y = -21\] and now we can solve for one variable and plug it into the other formula to solve for them. Try it out and I'm sure adamaero and I will help you figure it out. =)

Answer 9

So the answer would be -7 and 3

Answer 10

Would it? It's easy to check.

Answer 11

Thats what I got because -7 minus 3= -4 and -7 times 3= -21

Answer 12

I urge that you actually try to solve the equation though--koalabear won't always be there.