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Math / Algebra / Grade 8 / ml8ch

Use Sum and Difference Together - Practice 2

Add the two equations to remove one variable when its coefficients are opposites.

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Add the two equations to remove one variable when its coefficients are opposites. Then solve the simpler equation and check both originals.

Worked example

x + y = 10 and x - y = 4 add to 2x = 14, so x = 7 and y = 3.

x + y = 10 and x - y = 4 add to 2x = 14, so x = 7 and y = 3.
Worked model: x + y = 10 and x - y = 4 add to 2x = 14, so x = 7 and y = 3.
Question 1 Solve x + y = 12 and x - y = 6. What is x?
Question 2 Solve x + y = 11 and x - y = 9. What is x?
Question 3 Solve x + y = 13 and x - y = 9. What is x?
Question 4 Solve x + y = 15 and x - y = 9. What is x?
Question 5 Solve x + y = 14 and x - y = 12. What is x?