How do you solve the system 0.3x-0.2y=0.5 and x-2y=-5 using substitution?

1 Answer
Jun 12, 2017

x=5, y=5

Explanation:

Here we have a system of equations:

0.3x-0.2y=0.5
x-2y=-5

Let's focus on the second equation and rewrite the equation so that x is in terms of y:

x-2y=-5

x=2y-5

Now, we can substitute this equation for x into the first equation and solve for y:

0.3(2y-5)-0.2y=0.5

0.3(2y)-0.3(5)-0.2y=0.5

0.6y-1.5-0.2y=0.5

0.6y-0.2y=0.5+1.5

0.4y=2

y=2/0.4=20/4=5

Now that we have found y, we can (again) substitute it back into the second equation to find x:

x-2(5)=-5

x-10=-5

x=5

So, our answers are:

x=5 and y=5