3m + n =9 |×(5) 2m - 5n = -11 15m + 5n=45 2m - 5n=-11 15m+5n+2m+(-5n)=45+(-11) 17m=34|17 m=2 ----------------------- 4a - 2 = b 3a + 7b = 1,5 4a-b=2 |× 7 3a+7b=1,5 28a-7b=14 3a+7b=1,5 28a-7b+3a+7b=14+1,5 31a=15,5 a=2 ---------------------- 5x = 4 - 2y 4x + y = 3 5x+2y=4 4x+y=3 |×(-2) 5x+2y=4 -8x-2y=-6 5x+2y+(-8x)-2y=4+(-6) -3x=-2 |(-3) x=2/3 ------------------- 6x - 3y = 9 x + 5y = -9,5 |×(-6) 6x-3y=9 -6x-30y=57 6x-3y+(-6x)-30y=9+57 -33y=56 y=-1 i 23/33
Pierwszy 3m + n = 9 2m - 5n = -11 n = 9 - 3m 2m - 5n = -11 n=9-3m 2m - 5 (9 - 3m) = -11 n= 9 - 3m 2m - 45 + 15 m = -11 n= 9 - 3m 17m = 34 /: 17 n = 9 - 3m m = 2 n = 9 - 3*2 m = 2 n = 9 - 6 m = 2 n = 3 m = 2 Drugi 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 /:31 b = 4a - 2 a = 0,5 a= 0,5 b= 4 * 0,5 - 2 a = 0,5 b= 2 - 2 a = 0,5 b = 0 Tzreci 5x = 4 - 2y 4x + y = 3 4x + y = 3 5x = 4 - 2y y = 3 - 4x 5x = 4 - 2y y = 3 - 4x 5x = 4 - 2 ( 3 - 4x ) y = 3 - 4x 5x = 4 - 6 + 8x y = 3 - 4x 5x - 8x = 4 - 6 y = 3 - 4x 3x = - 2 / :3 y = 3 - 4x x = 2/3 - dwie trzecie - ułamek x = 2/3 y = 3 - 4 * 2/3 x = 2/3 y = 3 - 8/3 x = 2/3 y = 1/3 Czwarty 6x - 3y = 9 x + 5y = -9,5 6x - 3y = 9 x = -9,5 - 5y x = -9,5 - 5y 6 ( -9,5 - 5y ) -3y = 9 x = -9,5 - 5y -57 - 30y - 3y = 9 x = -9,5 - 5y -33y = 57 + 9 x = -9,5 - 5y -33y = 66 / : ( -33 ) x = -9,5 - 5y y = -2 y = -2 x = -9,5 - 5 * ( -2) y = -2 x = -9,5 + 10 y = -2 x= 0.5
