 Mixed Practice Below are four problems you can try, using the algebraic method of your choice. You'll need to decide which method is most efficient. You can check your answers at the bottom of the page.
Solution 1: 3x - 2y = 18 rearrange so we can use Comparison -2y = x + 2 -2y = -3x + 18 -2y = x + 2 -3x + 18 = x + 2 -4x = -16 x = 4 Substitute in first equation: 3(4) - 2y = 18 12 - 2y = 18 -2y = 6 y = -3 solution (4, -3) Solution 2: 8x - 3y = 12 Use Elimination 5x + 2y = -8 eliminate the y's 16x - 6y = 24 x 2 15x + 6y = -24 x 3 9x = 0 add the equations x = 0 8(0) - 3y = 12 -3y = 12 y = -4 solution (0, -4) Solution 3: 10x - 4y = 5 Use Substitution y = x + 1 10x -4(x + 1) = 5 10x - 4x - 4 = 5 6x = 9 x = 1.5 y = (1.5) + 1 = 2.5 solution (1.5, 2.5) Solution 4: y = 1/3x + 1 Use Substitution. Work with fractions to avoid having to round 5x - 2y = 3 6 3 Let's get rid of the fractions in equation two first: multiply by 6 y = 1/3x + 1 5x - 4y = 18 5x -4(1/3x + 1) = 18 substitute 5x - 4/3x - 4 = 18 15x/3 - 4/3x = 22 11x/3 = 22 11x = 66 x = 6 y = 1/3(6) + 1 substitute y = 3 solution (6, 3) |