How do you solve this equation -3x plus y equals 1 5x plus 2y equals 4?

Answer 1

If you mean:

-3x + y = 1

5x + 2y = 4

You must replace one letter, for example y, so it gives you an equation only using x.

If you bring everything to one side on the bottom equatin, it would read:

y = (4 - 5x)/2

Now use this equation to replace the y on the first equation:

-3x + (4-5x)/2 = 1 and solve for x

Find a common denominator, which is 2...

(-6x)/2 + (4-5x)/2 = 1

Combine...

(-6x + 4 - 5x) / 2 =1 which is:

(-11x + 4) / 2 = 1 Bring the 2 to the other side...

-11x + 4 = 2 Bring the 4 to the other side...

-11x = -2 Bring the -11 to the other side...

x = -2 / -11 or 2/11

Now plug in this number for x to solve for y:

5x + 2y = 4

5(2/11) + 2y = 4

10/11 + 2y = 4

2y = 4 - (10/11) common denominator is 11 so,

2y = 44/11 - 10/11

2y = 34/11 divide by 2

y = 34/11 * 1/2

y = 34/22 simplify

y = 17/11

x = 2/11 y = 17/11

If you replace both letters in the top equations with these answers, both sides should equal each other.