Equation1: 2x - 2y = 20, equation 2: x + 4y = 5First method (subtraction):Multiply equation1 by 2: 4x - 4y = 40Add the two equations together canceling out the y unknowns: 4x + x = 40 + 5Solve for x: 5x = 45, therefore x = 9Plug the value for x into equation2 and solve for y: 9 + 4y = 5, therefore y = -1Second method (substitution):Arrange equation2 to have x on one side and everything else on the other by subtracting 4y from both sides: x = 5 - 4ySubstitute this equation for x into equation1 and solve for y: 2(5 - 4y) - 2y = 20, therefore 10 - 10y = 20, therefore -10y = 10, therefore y = -1Plug the value of Y into equation2 and solve for x: x - 4 = 5, therefore x = 9

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