Solve the simultaneous equations 3x + y = 11 and 2x + y = 8.

First identify which unknown has the same coefficient. In this case it is y.Either add or subtract the two equations to eliminate y. In this case we subtract one equation from the other (can be either). 3x + y = 11- 2x + y = 8 x + 0y = 3which is x = 3.The value of x can now be substituted into either equation to find y.3(3) + y = 11 which is 9 + y = 11. Rearranging to find y we must minus 9 from both sides of the equation to get y on its own on one side of the equation.9 + y - 9 = 11 - 9 gives y = 2.We have now solved the simultaneous equations. We can check our answer is correct by substituting the values of x and y into either original equations. For example 3(3) + 2 = 9 + 2 = 11.




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Answered by Natasha C. Maths tutor

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