Answer: All real numbers
Step-by-step explanation:
You can take the cube root of positive and negative numbers, as well as zero.
1)
I:x-y=-7
II:x+y=7
add both equations together to eliminate y:
x-y+(x+y)=-7+7
2x=0
x=0
insert x=0 into II:
0+y=7
y=7
the solution is (0,7)
2)
I: 3x+y=4
II: 2x+y=5
add I+(-1*II) together to eliminate y:
3x+y+(-2x-y)=4+(-5)
x=-1
insert x=-1 into I:
3*-1+y=4
y=7
the solution is (-1,7)
3)
I: 2e-3f=-9
II: e+3f=18
add both equations together to eliminate f:
2e-3f+(e+3f)=-9+18
3e=9
e=3
insert e=3 into I:
2*3-3f=-9
-3f=-9-6
-3f=-15
3f=15
f=5
the solution is (3,5)
4)
I: 3d-e=7
II: d+e=5
add both equations together to eliminate e:
3d-e+(d+e)=7+5
4d=12
d=3
insert d=3 into II:
3+e=5
e=2
the solution is (3,2)
5)
I: 8x+y=14
II: 3x+y=4
add I+(-1*II) together to eliminate y
8x+y+(-3x-y)=14-4
5x=10
x=2
insert x=2 into II:
3*2+y=4
y=4-6
y=-2
the solution is (2,-2)
Answer: C(t) = 0.4t + 4
Step-by-step explanation:
Let t represent the total number of minutes of using a computer at the internet cafe.
The cafe charges an initial fee to use the computer and then an additional price per minute of usage. The initial charge to use the computers is $4 and the total charge would be $6 for 5 minutes of use. This is expressed as
5t + 4 = 6
5t = 6 - 4 = 2
t = 2/5 = 0.4
It means that the charge per minute would be $0.4
Therefore, the equation for the function C(t), representing the total cost of using a computer for t minutes at the internet cafe is
C(t) = 0.4t + 4
Answer:
please what is the question
