Answer: The correct option is
(E) 70.
Step-by-step explanation: We are given to find the number of triangles and quadrilaterals altogether that can be formed using the vertices of a 7-sided regular polygon.
To form a triangle, we need any 3 vertices of the 7-sided regular polygon. So, the number of triangles that can be formed is

Also, to form a quadrilateral, we need any 4 vertices of the 7-sided regular polygon. So, the number of quadrilateral that can be formed is

Therefore, the total number of triangles and quadrilaterals is

Thus, option (E) is CORRECT.
Answer:
B
Step-by-step explanation:
Triangle B because 128°>90°
Answer:
I believe it's the one on the bottom left
Step-by-step explanation:
I'm still taking my test so I'll come back later to tell you if it's correct.
Part a b2+49−(b−7)2
Distribute:
=b2+49+−b2+14b+−49
Combine Like Terms:
=b2+49+−b2+14b+−49
=(b2+−b2)+(14b)+(49+−49)
=14b
Answer:
=14b
part b
(2a+6b)2−24ab
Distribute:
=4a2+24ab+36b2+−24ab
Combine Like Terms:
=4a2+24ab+36b2+−24ab
=(4a2)+(24ab+−24ab)+(36b2)
=4a2+36b2
Answer:
=4a2+36b2