Start with

Add 2x to both sides:

Subtract 21 from both sides:

Divide both sides by 5. Since it is positive, we don't have to change the inequality sign:

So, the answer is 
First of all, you have to find the area of both triangles:


Or just 16 because there are 2 of the same triangles.
Now you have to find the area of the 3 rectangles.
The two that are in the front are 4*3 (l*h) or 12*2 (because there are 2 congruent rectangles. The area of those rectangles is 24 square mm.
Now you find the area of the back rectangle:
5.7*3 = 17.1
Finally, you add all the found numbers to figure out the surface area.
17.1 + 16 + 24 = 57.1 square millimeters.
Hope this helped,
Loafly
15. MP(5,11) S(3,5) M(x,y)
(3+x)/2 = 5 x=7
(5+y)/2 =-11 y=-27
M(7,-27) is the other point
Sense the two triangles are congruent you would use CPCTC.
Answer:
x + 52 + 78 = 180
Step-by-step explanation:
By angle sum property of a triangle:
