Answer:
Perimeter of a triangle = 2*(length + breadth)
SO = 2*18+41
= 77 is the perimeter
In the second step you should have subtracted the 2x to move it to the other or side of the equals sign
#2
2x - 4y = -2
2x + 3y = -16
------------------subtract
-7y = 14
y = 14/-7
y = -2
2x - 4y = -2
2x - 4(-2) = -2
2x + 8 = -2
2x = -2 -8
2x = -10
x = -10/2
x = -5
answer x = -2 and y = -5
check:
2(-5)- 4(-2) = -2
-10 +8 = -2
-2 = -2.....true
2x + 3y = -16
2(-5)+3(-2) = -16
-10 + (-6) = -16
-16 = -16...true