Question

Can you please help me solve this equation using substitution? I’ve been trying to solve it for so long and can’t do it.

2x-y=5 and 3x+y=-9

Answer 1

x=-4/5 y= -33/5

Explanation:

y=-3x-9

2x+3x+9=5

5x=-4

x=-4/5

Then plug it in into an equation.....2(-4/5)-y=5

-8/5-y=25/5

-y=33/5

y=-33/5

You can check if you want

Answer 2

x = -4/5, y = -6 3/5

Explanation:

The way to use substitution to solve is to isolate (Put it on one side without anything else on that side of the equation) a variable. We can use the first equation to isolate y. We can add y on both sides to get that 2x = y + 5 and then subtract by 5 on both sides to get that y = 2x - 5. Next, we can substitute 2x - 5 in for y in the second equation because y = 2x - 5. We would get that 3x + 2x - 5 = -9, so 5x - 5 = -9, and if you add by 5 on both sides, you get 5x = -4. Finally, we can divide by 5 on both sides to get that x = -4/5. If you want to find y, we can find it by substituting x into the equation 2x - 5 = y. 2 * -4/5 - 5 is equal to y, so -8/5 - 5 = y, and lastly, y = -6 3/5