Question

help please. medal for answer. !
find the solution to the system of equations by using either graphing or substitution.

y = 2x - 1 and y = x + 3
a. 4,7
b. 7,4
c. -7, -4
d. infinite solutions

Answer 1

So first, we can immediately eliminate D. In order for it to be an infinite solution, the solution must be true for every value of x.

So if we decide x = 1, we would have:
2(1) - 1 and (1) + 3
2 - 1 and 1 + 3
1 and 4

Does that part make sense?

Answer 2

yes.

Answer 3

Would you like to use substitution here?

Answer 4

sure.

Answer 5

So, the y's are by itself now.

We know that y is equal to 2x - 1, and we know that y is also equal to x + 3

Because these are both equal to y, they are equal to each other.


2x - 1 = x + 3

Answer 6

So now you have to use Algebra to make x by itself. What is x here?

Answer 7

sorry, im lost. i got the first part. just lost now.

Answer 8

Can we say that 7-4 and 6-3 will both equal 3?

Answer 9

yes.

Answer 10

So would you also agree that 7-4 = 6-3? Because they are both equal to 3?

Answer 11

yes

Answer 12

That same thing is going to apply to your problem. The y's will both have the same value, because only one value can be applied to y.

2x-1 = x+3 because they will both yield the same value, just like my example above.

Does that make sense?

Answer 13

yes

Answer 14

So now, we need x on one side, and a numerical value on the other.



What will x equal here?