Hey there :)
Before translating the sentence into mathematics, let r represent 'a number'
5 times a number = 5r
2 times that number = 2r
The difference between them = 5r - 2r
* Your equation
5r - 2r
* Solving the equation
= 5r - 2r
= 3r
Answer:
...................
Step-by-step explanation:
............................
A regular trapezoid is shown in the picture attached.
We know that:
DC = minor base = 4
AB = major base = 7
AD = BC = lateral sides or legs = 5
Since the two legs have the same length, the trapezoid is isosceles and we can calculate AH by the formula:
AH = (AB - DC) ÷ 2
= (7 - 5) ÷ 2
= 2 ÷ 2
= 1
Now, we can apply the Pythagorean theorem in order to calculate DH:
DH = √(AD² - AH²)
= √(5² - 1²)
= √(25 - 1)
= √24
= 2√6
Last, we have all the information needed in order to calculate the area by the formula:

A = (7 + 5) × 2√6 ÷ 2
= 12√6
The area of the regular trapezoid is
12√6 square units.
Answer:
-13a^2 + 170ab - 13b^2.
Step-by-step explanation:
1. 36(a+b)^2 - 49(a-b)^2
This is the difference of 2 squares: a^2 - b^2 = (a + b)(a - b).
36(a+b)^2 - 49(a-b)^2
= (6(a + b) + 7(a - b))( 6(a + b) - 7(a - b))
= (6a + 7a + 6b - 7b)( 6a - 7a + 6b + 7b)
= (13a - b)(-a + 13b)
If you require the expansion of this it is:
-13a^2 + 170ab - 13b^2.