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c. (1/2, 8)

Step-by-step explanation:

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.

Choose one of the equations and solve it for x by isolating x on the left hand side of the equal sign.

-2x + y = 7

Step 1: Subtract y from both sides of the equation.

-2x = -y + 7

Step 2: Divide both sides by -2

x = 1/2y - 7/2

Substitute what you see above this statement for y in the other equation.

6(1/2y - 7/2) + y = 11

Step 3: Multiply 6 by 1/2y - 7/2.

3y - 21 + y = 11

Step 4: Combine y and 3y.

4y - 21 = 11

Step 5: Add 21 to both sides

4y = 11 + 21

4y = 32

Step 6: Divide both sides by 4.

y = 32/4

y = 8

Step 7: Substitute 8 for y in x = 1/2y - 7/2 Because the resulting equation contains only one variable, you can solve for x directly.

x = 1/2(8) - 7/2

Step 8: Multiply 1/2 by 8.

x = 4 - 7/2

Step 9: Add -7/2 to 4.

x = 1/2

The system is now solved, and we get C (1/2, 8) as our answer.