Answer:
25-7
Step-by-step explanation:
"Substitute for": Replace x with ____
Since it is given that x = 25 -y, we can replace the x in 5x + y = 10 with 25 - y by the substitution property of equality.
the center is at the origin of a coordinate system and the foci are on the y-axis, then the foci are symmetric about the origin.
The hyperbola focus F1 is 46 feet above the vertex of the parabola and the hyperbola focus F2 is 6 ft above the parabola's vertex. Then the distance F1F2 is 46-6=40 ft.
In terms of hyperbola, F1F2=2c, c=20.
The vertex of the hyperba is 2 ft below focus F1, then in terms of hyperbola c-a=2 and a=c-2=18 ft.
Use formula c^2=a^2+b^2c
2
=a
2
+b
2
to find b:
\begin{gathered} (20)^2=(18)^2+b^2,\\ b^2=400-324=76 \end{gathered}
(20)
2
=(18)
2
+b
2
,
b
2
=400−324=76
.
The branches of hyperbola go in y-direction, so the equation of hyperbola is
\dfrac{y^2}{b^2}- \dfrac{x^2}{a^2}=1
b
2
y
2
−
a
2
x
2
=1 .
Substitute a and b:
\dfrac{y^2}{76}- \dfrac{x^2}{324}=1
76
y
2
−
324
x
2
=1 .
X - 2y = -24
x - y = 4
Isolate x in the first equation by adding 2y to both sides.
x = -24 + 2y
Now plug in this value of x into the second equation.
(-24 + 2y) - y = 4
Solve. Combine all like terms, 2y - y.
-24 + y = 4
Add 24 to both sides to isolate y.
y = 28
Now plug y back into the first equation to find x.
x - 2(28) = -24
x - 56 = -24
Add 56 to both sides to isolate x.
x = 32
The solution is (32, 28).
Answer: 
Step-by-step explanation:
Given
New mail carrier takes 4 hours for delivery i.e.
New mail carrier completes 
part of work in 1 hour
Old mail carrier takes 3 hours for delivery i.e.
mail carrier completes 
part of work in 1 hour
If they work together, they complete the work in x hours i.e.
The answer is C, hope this helps
