Question

SZYBKO PLISSS POMOCYYYYYYY!
SZYBKOOO
rozwiąż równanie i sprawdz otrzymane wyniki metodą dowolną,'

a 3x+y=-3
-x+3y=11

b x+y=6
5x+y=-2

c x-y+2=0
2y=x+5

d 1/2x + y=4
2x-4y=8

e 3x-2=2y
y-6x=-5/2

f 1/2x - 1/2y=-4
-2x+1/3y=8

Answer 1

A) 3x + y = -3
-x + 3y = 11 / * 3

3x + y = -3
-3x + 9y = 33
10y = 30 / : 10
y = 3
3x + 3 = -3
3x = -6 / : 3
x = -2
spr. -(-2) + 3 * 3 = 11
2 + 9 = 11 OK

b) x + y = 6 / * (-1)
5x + y = -2

-x - y = -6
5x + y = -2
4x = -8 / : 4
x = -2
-2 + y = 6
y = 8
spr. 5 * (-2) + 8 = -2
-10 + 8 = -2 OK

c) x - y + 2 = 0
2y = x + 5

x - y = -2
-x + 2y = 5
y = 3
x - 3 = -2
x = 1
spr. -1 + 2 * 3 = 5
-1 + 6 = 5 OK

d) 1/2x + y = 4 / * 4
2x - 4y = 8

2x + 4y = 16
2x - 4y = 8
4x = 24 / : 4
x = 6
2 * 6 + 4y = 16
12 + 4y = 16
4y = 4 / : 4
y = 1
spr. 2 * 6 - 4 * 1 = 8
12 - 4 = 8 OK

e) 3x - 2 = 2y
y - 6x = -5/2

3x - 2y = 2
-6x + y = -5/2 / * 2

3x - 2y = 2
-12x + 2y = -5
-9x = -3 / : (-9)
x = 1/3
3 * 1/3 - 2y = 2
1 - 2y = 2
-2y = 1 / : (-2)
y = -1/2
spr. -12 * 1/3 + 2 * (-1/2) = -5
-4 - 1 = -5 OK

f) 1/2x - 1/2y = -4 / * 2
-2x + 1/3y = 8 / * 3

x - y = -8
-6x + y = 8
-5x = 0
x = 0
-y = -8 / * (-1)
y = 8
spr. -6 * 0 + 8 = 8
8 = 8 OK