Odpowiedź :
1. x +y= 70
2x-1/2y=40
x = 70-y
2(70-y)- 1/2y=40
x=70-y
140 - 2y - 1/2y=40
x= 70-y
-5/2y= -100
x= 70-y
y=40
x= 70-40
y=40
x= 30
y=40
tyle jestem w stanie ci pomóc
2x-1/2y=40
x = 70-y
2(70-y)- 1/2y=40
x=70-y
140 - 2y - 1/2y=40
x= 70-y
-5/2y= -100
x= 70-y
y=40
x= 70-40
y=40
x= 30
y=40
tyle jestem w stanie ci pomóc
1.
x+y =70
2x-½y=40|×(2)
x+y=70
4x-y=80
_________
5x=150|:5
x=30
y=70-x
y=70-30
y=40
Odp.40 i 30
2.
¾x+⅕y=13|x(-20)
2x-¼y=19|x20
-15x-4y=-260|x5
40x-5y=380|x(-4)
-75x-20y=-1300
-160x+20y=-1520
______________
-240x=-2820
x=11,75
40x-380=5y
40x11,75-380=5y
90=5y|:5
y=18
Odp. 18 i 11,75
3.¾x+⅕y=110|x20
⅘x-¼y=71|x20
15x+4y=2200|x5
16x-5y=1420|x4
75x+20y=11000
64x-20y=5680
_________
139x=16680|:139
x=120
5y=16x120-1420
5y=500
y=100
odp. 120 i 100
x+y =70
2x-½y=40|×(2)
x+y=70
4x-y=80
_________
5x=150|:5
x=30
y=70-x
y=70-30
y=40
Odp.40 i 30
2.
¾x+⅕y=13|x(-20)
2x-¼y=19|x20
-15x-4y=-260|x5
40x-5y=380|x(-4)
-75x-20y=-1300
-160x+20y=-1520
______________
-240x=-2820
x=11,75
40x-380=5y
40x11,75-380=5y
90=5y|:5
y=18
Odp. 18 i 11,75
3.¾x+⅕y=110|x20
⅘x-¼y=71|x20
15x+4y=2200|x5
16x-5y=1420|x4
75x+20y=11000
64x-20y=5680
_________
139x=16680|:139
x=120
5y=16x120-1420
5y=500
y=100
odp. 120 i 100