Question

Rozwiąż metodą podstawiania.

2x + y = 5
4x - y = 10

2x - y = -4
x - 2y = 7

½x + 3y = 11
¼x - 2 = -5

½x + ¼y = -2
5x - 3y = 2

½x + ¼y = -2
5x - 3y = 2

dzieki :)

Answer 1

Y=5-2x
4x-(5-2x)=10
4x-5+2x=10
6x=15 /:6
x=15/6
y=5-2*15/6
y=0

y=-4-2x
x-2(-4-2x)=7
x+8+4x=7
5x=15 /:5
x=3
y=-4-2*3
y=-10

1/2x+3y=11 /*2
x=22-6y
1/4x-2=-5 /*4
x-8=-20
22-6y-8=-20
-6y=-36 /:-6
y=6
x=22-6*6
x=-14

1/2x+1/4y=-2 /*4
2x+y=-8
y=-8-2x
5x-3y=2
5x-3*(-8-2x)=2
5x+24+6x=2
11x=-22 /:11
x=-2
y=-8-2*(-2)
y=-4

Answer 2

1.
2x + y = 5
4x - y = 10

y = 5 - 2x
4x - 5 - 2x = 10
2x = 15 |: 2
x = 7,5

y = 5 - 2 * 7,5
y = 5 - 15
y = -10

x = 7,5
y = -10

2.

2x - y = -4
x - 2y = 7

x = 7 + 2y
2(7 + 2y) - y = -4
14 + 4y - y = -4
3y = -18 |:3
y = -6

x = 7 + 2 * - 6
x = 7 + 12
x = 19

x = 19
y = -6

3.

½x + 3y = 11
¼x - 2 = -5

¼x = -5 + 2
¼x = -3 |: ¼
x = -3 * 4
x = -12

½ * -12 + 3y = 11
-6 + 3y = 11
3y = 11 + 6
3y = 17 |:3
y = 5⅔

x = -12
y = 5⅔

4.
½x + ¼y = -2 |*4
2x + y = -8

y = -8 - 2x
5x - 3y = 2
5x - 3 * ( -8 - 2x ) = 2
5x + 24 + 6x = 2
11x = -22 |:11
x = -2

y = -8 - 2*(-2)
y = -4


(przykład 4 i 5 są takie same)

Answer 3

Rozwiązanie w załączniku ;))