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: If a shape has 4 congruent sides, then it is a rhombus.
Step-by-step explanation: I just added the words in the appropriate places.
Answer:
where is the picture???
what are the given lengths?
150 is smaller than 200 so 25 is smaller than 40, but 25, in perspective to the numbers, is much smaller than 40. Ana is faster.
Check:
Takashi: 200 divided by 400 equals 5 yd/sec
Ana: 150 divided by 25 equals 6 yd/sec
Answer:
The error E = ± 4.04 %
Step-by-step explanation:
Solution:-
- The sample data is used to estimate the population proportion ( p ).
- The success p^ = success percentage = 40 %
- The confidence interval CI = 98%
- The sample size n = 800
- The margin of error E:
- The margin of error "E" for estimation of population proportion ( p ) is given by:

Where, Z-critical value is defined by the significance level:
P ( Z < Z-critical ) = α / 2
Where, α : Significance level
α = 1 - CI
P ( Z < Z-critical ) = (1 - 0.98) / 2
P ( Z < Z-critical ) = 0.01
Z-critical = 2.33
- The error E of estimation is:

- The error E = ± 4.04 %