Answer:
x=1
y=−5
Explanation:
Consider the first equation. Subtract 2x from both sides.
y−2x=−7
Consider the second equation. Subtract 4x from both sides.
−y−4x=1
To solve a pair of equations using substitution, first solve one of the equations for one of the variables. Then substitute the result for that variable in the other equation.
y−2x=−7,−y−4x=1
Choose one of the equations and solve it for y by isolating y on the left hand side of the equal sign.
y−2x=−7
Add 2x to both sides of the equation.
y=2x−7
Substitute 2x−7 for y in the other equation, −y−4x=1.
−(2x−7)−4x=1
Multiply −1 times 2x−7.
−2x+7−4x=1
Add −2x to −4x.
−6x+7=1
Subtract 7 from both sides of the equation.
−6x=−6
Divide both sides by −6.
x=1
Substitute 1 for x in y=2x−7. Because the resulting equation contains only one variable, you can solve for y directly.
y=2−7
Add −7 to 2.
y=−5
The system is now solved.
y=−5,x=1