Thread: Need help with integers and equations...

I have to perform the following math problem:

Select any two integers between -12 and +12 which will become solutions to a system of two equations. Then write TWO EQUATIONS that have your two integers as solutions and solve the system of equations using the addition/subtraction method.

I am not quite sure how to even get started. Please help! Thanks

Originally Posted by Kelmo7

I have to perform the following math problem:

Select any two integers between -12 and +12 which will become solutions to a system of two equations. Then write TWO EQUATIONS that have your two integers as solutions and solve the system of equations using the addition/subtraction method.

I am not quite sure how to even get started. Please help! Thanks

well, pick the two numbers, and make equations with them

example, i pick 1 and 7, because i had 1 sandwich for breakfast this morning and your name is kelmo7. and just because, let x = 1 and y = 7


ok, so 2(1) + 3(7) = 23

so my first equation is 2x + 3y = 23

another random arrangment:

5(1) - 2(7) = -9

so another equation is 5x - 2y = -9

so my system is:

2x + 3y = 23 ...................(1)
5x - 2y = -9 ....................(2)


come up with another system

Originally Posted by Kelmo7

I have to perform the following math problem:

Select any two integers between -12 and +12 which will become solutions to a system of two equations. Then write TWO EQUATIONS that have your two integers as solutions and solve the system of equations using the addition/subtraction method.

I am not quite sure how to even get started. Please help! Thanks

Edit: Jhevon, this is the first post I've made today and you beat me to it!

Let's say you pick (2, 3).

Make up an expression with x and y, let's say 2x + 3y. How much is that? If you substitute the ordered pair (2, 3), the result is 13. Thus, your first equation is:

2x +3y = 13

Make up a second expression with x and y, let's say x + y. How much is that? Substituting, we have your second equation:

x + y = 5

The system is easy to solve using addition/subtraction method.

Originally Posted by Kelmo7

I have to perform the following math problem:

Select any two integers between -12 and +12 which will become solutions to a system of two equations. Then write TWO EQUATIONS that have your two integers as solutions and solve the system of equations using the addition/subtraction method.

I am not quite sure how to even get started. Please help! Thanks

Pick two integers. I will pick x1=2 and x2=-3.

To come up with 2 equations, go ahead and write 2 expressions involving x1 and x2. Out of thin air, I will pick

2 x1 + x2
x1 - x2


Now plug the values of x1 and x2 to see what those expressions equal.

2 x1 + x2 = 1
x1 - x2 = 5

Now you have your 2 equations with 2 (known) unknowns. Try practicing with your own expressions. The only thing you have to be careful of is that the 2 expressions can't be the same up to a constant multiple.

For example, don't pick x1 + x2 and 2 x1 + 2 x2. The second is just 2 times the first. This won't lead to two non-equivalent equations.

Enjoy.

Originally Posted by masters

Edit: Jhevon, this is the first post I've made today and you beat me to it!

hehe, sorry dude