Answer:

Step-by-step explanation:
The sum you are trying to understand is this.

Remember that in general when you have a geometric series
you have that
and that equality is true as long as
.
Therefore here we have
and 
Therefore we can use the formula and

5x-2x=7x+2x-24
3x = 9x -24
3x - 9x = -24
-6x = -24
x = -24/-6
x = 4
A triangle is a three-edged polygon with three vertices. It is a fundamental form in geometry. The length of the legs XY and YZ is equal to 39 units.
<h3>What is a triangle?</h3>
A triangle is a three-edged polygon with three vertices. It is a fundamental form in geometry. The sum of all the angles of a triangle is always equal to 180°. An isosceles triangle has two sides out of three equal.
A.) The value of n can be found by equating XY and XZ together,
XY = XZ
9n + 12 = 15n - 6
12 + 6 = 15n - 9n
18 = 6n
n = 3
Hence, the value of n is 3.
The length of different legs of the triangle is,
B.) XY = 9n + 12 = 9(3) + 12 = 27 + 12 = 39
C.) YZ = 15n - 6 = 15(3) - 6 = 45 - 6 = 39
Hence, the length of the legs XY and YZ is equal to 39 units.
Learn more about Triangle:
brainly.com/question/2773823
#SPJ1