Question

3x+y=4
x=1

x+y=9
x-y=1

3x+y=9
2x-3y=6

4x-5y=33
x-y=7
dau coroană și abonare

Answer 1

3x+y=4
x=1
Adica:
3•1+y=4
3+y=4
y=4-3
y=1

x+y=9
x-y=7
2x=16
x=16:2
x=8
8-y=7
-y=7-8
-y=-1 /•(-1)
y=1

3x+y=9
2x-3y=6
9x+3y=27
2x-3y=6
11x=33
x=33:11
x=3
2•3-3y=6
y=0

4x-5y=33
x-y=7
4x-5y=33
-4x+4y=-28
-y=5 /•(-1)
y=-5
x-(-5)=7
x=2

Answer 2

3x+y=4
x=1
3x=3
3+y=4
y=4-3
y=1

x+y=9
x-y=1
x=y+1
y+1+y=9
2y=9-1
2y=8
y=8:2
y=4
x=4+1
x=5

3x+y=9
2x-3y=6
2x=3y+6

9x+3y=27
2x-3y=6
11x=33
x=3
2x3-3y=6
y=0

4x-5y=33
x-y=7
-4x-4x(-y)= -4x7
4x-5y=33
-4x+4y= -28
-y = 5
y= -5
x-(-5)=7
x=2