Well if you want a why it is because that is the formula for a parallelogram but the answer is... well idk you need to add the height too not just the base :3
Du to the triangle is an Equilateral triangle, both angles are equal.
Now we have a straight angle RTU which equals 180 degrees so,
<RTS + <STU = 180
5x + 5x -30 = 180
10x = 210
x = 21
8y-9-4y+5=12y-4-5y
4y-4= 7y-4
Add 4 to both sides
4y=7y. The only answer is 0
Simplifying x + 3 + x + 4 = x + 7 + 2x + 7 Reorder the terms: 3 + 4 + x + x = x + 7 + 2x + 7 Combine like terms: 3 + 4 = 7 7 + x + x = x + 7 + 2x + 7 Combine like terms: x + x = 2x 7 + 2x = x + 7 + 2x + 7 Reorder the terms: 7 + 2x = 7 + 7 + x + 2x Combine like terms: 7 + 7 = 14 7 + 2x = 14 + x + 2x Combine like terms: ...