Question

Please help me !

What is the best first step for solving the given system using substitution while avoiding fractions?

2x+6y=7
6x+18y=24

Solve for x in the first equation.
Solve for y in the first equation.
Solve for x in the second equation.
Solve for y in the second equation.

Answer 1

solve for x in the second equation first

Answer 2

Solve for x in the second equation.

Explanation:

To solve a system of equations by substition you have to solve one of the equations for X or Y and then substitute that value on the X of the other equation, if you want to avoid fractions, you can use the x of the secon equation, like this:

`6x+18y=24\\6x=24-18y\\x=(24-18y)/(6) \\x=4-3y`

So by solving X for the second equation you avoided fractions when substituting the value for X on the first equation.