a) {4a-2=b {3a+7b=1,5 b) {5x=4-2y {4x+y=3 c) {6x-3y=9 {x+5y=-9.5 Prosze pomózcie

4a-2=b 3a+7b=1.5 b=4a-2 3a +7(4a-2)=1.5 b=4a-2 3a+28a-14=1.5 b=4a-2 31a-14=1.5 b=4a-2 31a=1.5+14 b=4a-2 31a=15.5|:31 a=2 b=4*2-2 b=8-2 b=6

a) 4a-2=b 3a+7b=1,5 b=4a-2 3a+7(4a-2)=1,5 b=4a-2 3a+28a-14=1,5 b=4a-2 31a=1,5+14 b=4a-2 31a=15,5 b=4a-2 a= 1/2 b=0 a= 1/2 ---------------------- b) 5x=4-2y 4x+y=3 y=3-4x 5x=4-2(3-4x) y=3-4x 5x=4-6+8x y=3-4x 5x-8x=-2 y=3-4x -3x=-2 /*(-1) y=3-4x 3x=2 y=3-4x x=2/3 y=3-4*2/3 x=2/3 y=1/3 x=2/3 ---------------- c) 6x-3y=9 x+5y=-9.5 x=-9,5-5y 6(-9,5-5y)-3y=9 x=-9,5-5y -57-30y-3y=9 x=-9,5-5y -33y=9+57 x=-9,5-5y -33y=66 /*(-1) x=-9,5-5y 33y=-66 x=-9,5-5y y=-2 x=-9,5-5(-2) y=-2 x=1/2 y=-2

a){4a-2=b {3a+7b=1,5 b=-4a+2 3a+7(-4a+2)=1,5 b=-4a+2 3a-28a+14=1,5 b=-4a+2 -25a=1,5-14 b=-4a+2 25a=-12,5/"(-25) b=-4a+2 a=0,5 b=4*0,5+2 a=0,5 b=4 a=0,5 b){5x=4-2y {4x+y=3 5x=4-2y y=3-4x 5x=4-2(3-4x) y=3-4x 5x=4-6+8x y=3-4x -3x=-2/:(-3) y=3-4x x= 2/3 y=3-4x x= 2/3 y=3-4* 2/3 x= 2/3 y=3/3 - 8/3 x= 2/3 y=-1 i 2/3 c){6x-3y=9 {x+5y=-9.5 6x-3y=9 x= -9,5-5y 6(-9,5-5y)- 3y=9 x= -9,5-5y -57-30y-3y=9 x= -9,5-5y -33y=66 /:(-33) x= -9,5-5y y=-2 x=-9,5-5 *(-2) y=-2 x=0,5