Sarah and Kayla both solved the problem below. Who solved it correctly? Identify the mistake for the person who solved it incorrectly.
Sarah
Kayla
5x - 15 - 3x = 10 - (-3x + 20)
5x - 15 - 3x = 10 -(-3x + 20)
2x - 15 = 10 + 3x - 20
2x - 15 = 10 + 3x – 20
2x - 15 = -10 + 3x
2x - 15 -10 + 3x
-3x
- 3x
+3x
+ 3x
- 1x - 15 = -10
5x - 15 = -10
+ 15
+15
+15
+15
- 1x = 5
5x = 5
x = -5
X = 1
What property did they use during that step
to solve it correctly?

            gh

Step-by-step explanation:

i don't really know i need points

it would open into a square depending on the type of envelope i’m not sure about the second part

the answer is:

the lateral area is equal to

to find the lateral area of the square pyramid, first we need to find the perimeter of the base, and then, find the lateral area using the following formulas:

where,

s, is the base length

slant height, is the height of a the side of the pyramid

we are given:

now, calculating the perimeter of the base, we have:

then, calculating the lateral area:

hence, we have that the lateral area is equal to

have a nice day!