Summary of methods to solve systems method equal values this method is most efficient when both equations in form example substitution -2x + one variable is alone on one side of one equation equations in standard form with opposite coeficients. x + 2y = 21 36 27 elimination: add to eliminate one variable. elimination: multiply one equation to eliminate one variable elimination: multiply both equations to eliminate one variable. equations in standard form. to eliminate multiplied to create opposite terms one equation can be 3.6+2y7 when nothing else works. in this case you could multiply the first equation by 3 and the second equation by-2. then add to eliminate the opposite terms. 3x + 2y = 7 problems 1 2x + y = 6 -2x + y = 2 2 -3x+ y0 -6x + 5y = -10 3. 2x - 3y = -9 x -2 4 y-x=4 2y+x=8 5. 2x - y = 4 6. 4x - 4y=14 2x - 4y - 8 7. 6x – 2y = -16 4.x+y=1 8. 6x - y = 4 6x + 3y = -16 9. 2x - 2y = 5 2x - 3y = 3