solve the system of equations 5x-3y=-1 and Y=2x

Question

solve the system of equations 5x-3y=-1 and Y=2x

Answer 1

Hey Melissa -- 3y's means 6x's ... and 3y= 5x +1 ... the extra x is worth 1 ...

since a y is worth 2x's ==> solves at (1,2) ... Best wishes, ma'am :)

Answer 2

Hi Melissa;

5x-3y=-1 and y=2x

I believe this requires application of a concept called substitution.

Let's begin with...

5x-3y=-1

Because y=2x, we can substitute...

(5x)-3(2x)=-1

5x-6x=-1

-x=-1

x=1

 

Let's plug this in and establish y...

5(1)-3y=-1 and y=2(1)

5-3y=-1 and y=2

-3y=-6

y=2

Answer 3

Hi Melissa,

 

For this one, all you need to do is substitute that 2x in for the Y in the first equation.

 

When you do this, you'll be left with 5x - 3(2x) = -1

 

Remember that you can combine like terms (2x + 2x = 4x, etc.) so you can simplify that left side of the equation, which leaves you with some division that you need to do, and your resulting answer should be a positive number.

 

Hope this helps!