a) 2x-11y=73/: 3x-4y=47 x - 5,5y = 36,5 3x-4y=47 x=5,5y + 36,5 3 (5,5y +36,5) - 4y = 47 x=5,5y + 36,5 16,5y + 109,5 - 4y = 47 x=5,5y + 36,5 12,5y = 47- 109,5 x=5,5y + 36,5 12,5y = -62,5/:12,5 x=5,5y + 36,5 y = -5 x=5,5 * (-5) + 36,5 y= -5 x = 9 y = 5 b) -2x+5y=-10 /-2 7x-4y=8 x - 2,5y = 5 7x-4y=8 x = 5 + 2,5y 7(-5 + 2,5y) - 4y = 8 x = 5 + 2,5y 35 + 17,5y - 4y =8 x = 5 + 2,5y 13,5y = - 27/ :13,5y x = 5 + 2,5y y = (-2) x = 0 y = (-2) c) 9x+8y=1 5x-6y=11/ :5 9x+8y=1 x -1,2y = 2,2 9x+8y=1 x = 1,2y +2,2 9 (1,2y + 2,2) + 8y = 1 x = 1,2y +2,2 10,8y + 19,8 + 8y = 1 x = 1,2y +2,2 18,8y = -18,8 /:18,8 x = 1,2y +2,2 y = -1 x = 1,2 * (-1) +2,2 y = -1 x = 1
a) 2x-11y=73 3x-4y=47 2x=73-11y /2 3x-4y=47 x=⁷³/²-¹¹/₂y 3(⁷³/²-¹¹/₂y)-4y=47 x=⁷³/²-¹¹/₂y ²¹⁹/₂+³³/₂y-4y=47 x=⁷³/²-¹¹/₂y ²⁵/₂y=47-²¹⁹/₂ x=⁷³/²-¹¹/₂y ²⁵/₂y=¹²⁵/₂ /(²⁵/₂) x=⁷³/₂-¹¹/₂y y=5 x=⁷³/₂-¹¹/₂(2) y=5 x=⁷³/₂-11 y=5 x=⁵¹/₂ b) -2x+5y=-10 7x-4y=8 -2x=-10-5y /(-2) 7x-4y=8 x=5+⁵/₂y 7(5+⁵/₂y)-4y=8 x=5+⁵/₂y 35+³⁵/₂y-⁸/₂y=8 x=5+⁵/₂y ²⁷/₂y=8-35 /(²⁷/₂) x=5+⁵/₂y y=-27ײ/₂₇ x=5+⁵/₂y y=-2 x=5+⁵/₂(-2) y=-2 x=5-5 y=-2 x=0 c) 9x+8y=1 5x-6y=11 9x=1-8y /9 5x-6y=11 x=¹/₉-⁸/₉y 5(¹/₉-⁸/₉y)-6y=11 x=¹/₉-⁸/₉y ⁵/₉-⁴⁰/₉y-⁵⁴/₉y=11 x=¹/₉-⁸/₉y -⁹⁴/₉y=11-⁵/₉ /(-⁹⁴/₉) x=¹/₉-⁸/₉y y=⁹⁴/₉×(-⁹/₉₄) x=¹/₉-⁸/₉y y=-1 x=¹/₉-⁸/₉(-1) y=-1 x=1
