Answer:
Step-by-step explanation:
If the diagonals of the rectangle are congruent,
AC = BD
By using formula to calculate the distance between two points,
Distance between two points = 
Distance between A(0, -3) and C(2, 8),
AC = 
= 
= 
Similarly, distance between two points B(-4, 0) and D(6, 5),
BD = 
= 
= 
Therefore, both the diagonals are congruent.
Hence, given quadrilateral ABCD is a rectangle.
Answer:
2.45 gallons of gasoline were in the tank before.
Step-by-step explanation:
Consider the provided information.
The tank can hold
gallons of gasoline when completely full. He had some gas in the tank and added 10.3 gallons of gasoline to fill it completely.
We need to find: How many gallons of gasoline were in the tank before Javier added some?
For this, we need to subtract added gallons of gasoline from the capacity of the tank.



Hence, 2.45 gallons of gasoline were in the tank before.
Answer:
6 2/3
Step-by-step explanation:
2 2/5 * 2 7/9
Change each number to an improper fraction
2 2/5 = (5*2+2)/5 = 12/5
2 7/9 = (9*2+7) = 25/9
12/5 * 25/9
Rewriting
25/5 * 12/9
5/1 * 4/3
20/3
Now changing to a mixed number
3 goes into 20 6 times with 2 left over
6 2/3
The area is given by
A = (5 + 2x) * (10 + 2x) - 50
Rewriting we have:
A = 50 + 10x + 20x + 4x ^ 2 -50
Rewriting we have:
A = 4x ^ 2 + 30x
Substituting the value of the area we have:
54 = 4x ^ 2 + 30x
Rewriting:
4x ^ 2 + 30x - 54 = 0
We look for the roots:
x1 = -9
x2 = 3/2
We take the positive root:
x2 = 3/2
Answer:
the value of x is:
x = 3/2