1. 4x + 10y = 2 /×7
7x + 15y = -3 /×(-4)
28x + 70y = 14
-28x + 60y = 12
10y = 26 /÷10
y = 2,6
4x + 26 = 2
4x = -24 /÷4
x = -6
odp.B
2. x² + 3x - y² - 3y = (x-y)(x+y)
4x + 3y = 2
x² + 3x - y² - 3y = x²-y²
4x + 3y = 2
3x - 3y = 0
4x + 3y = 2
7x =2 /:7
x = 2/7
4 × 2/7 + 3y = 2
8/7 + 3y = 2
3y = 6/7 /÷3
y = 2/7
ODP.A.
3. 2x - 3y =6
1/2y + 1 =1/3x
2x - 3y =6
1/2y -1/3x = -1 /×6
2x - 3y =6
3y -2x = -6
0 = 0
ODP. A
4.wystarczy odp. B
5.wystarczy odp. B.
6.wystarczy odp. B
7. x + 5 = 10
10:2=5
5+1=6
ODP. B
8.x + y = 135 /×(-0,9)
0.9x + y +2 =125
-0,9x - 0,9y = -121,5
0.9x + y +2 =125
0,1y = 1.5 /:0,1
y= 15
135- 15 = 120
ODP. C
9.wystarczy odp. B
10. y + x = 2x + 1
x + 2y + 5 = 2(2x+1)
y + x = 2x + 1
x + 2y + 5 = 4x+2
y - x = 1 /×(-3)
-3x + 2y = -3
-3y + 3x = -3
-3x + 2y = -3
-y = -6 /×(-1)
y = 6
6 - x = 1
x = 5
Obw. 6 × (2 × 5 + 1) = 66
ODP. B
11. 7k + 6g = 1,2 /*3
3k + 4g = 0.7 /*(-7)
21k + 18g = 3.6
-21k -28g = -4.9
-10g = -1.3 /:(-10)
g = 0,13
3k + 0,52 = 0,7
3k = 0,18 /:3
k = 0,06
130-60 = 70
ODP. D
12. x+y = 1,5 /*(-0,925)
0,925x + 0,800y =0,850 * 1,5
-0,925x-0,925y - -1,3875
0,925x + 0,800y =1,275
-0,125y = -0,1125 /:(-0,125)
y = 0,9
x + 0.9 = 1.5
x = -0.6
ODP.B
