Hello :
the nth term ( general term of an arithmetic sequence is :
An =A1+(n-1)d ....a common difference is : d , A1 : the first terme
A1 = 5 and : d = 1 - 5 = - 4 n = 21
A21 = 5 + (21 -1)(-4)
A21 = 5 - 80 = -75
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Answer- A-16
Because when doing completing the square, you divide the coefficient of x by 2, which is 4, and the square it which is 16
Answer:
B
C
F
D
H
A
G
E
Step-by-step explanation:
Ok. They are trying to reconstruct the smaller looking triangle in the bigger triangle using angle A as the common angle.
The first statement is always the given.
Second they constructed line segment XY into the bigger triangle so that XY is parallel to BC.
Third, from the construction of the parallel lines we can now find corresponding angles that are congruent. This would be the use of F.
Since we have all three angles in triangle AXY and triangle ABC, then the construction of the smaller triangle we made inside the bigger triangle is similar to the bigger triangle. So we have the triangles are similar. You could say E or D here in my opinion. This is choice D.
Fifth the creation of those fractions of sides being equal comes from us knowing the corresponding sides of similar triangles are proportional. This is choice H.
Things looked cut off for the sixth thing so I can't fully read it, but it is possible a substitution has occured.
The seventh thing is a congruence statement which can be proven by a congruence postulate. The only one listed is SAS. So that is G.
The last thing, since the triangle construction is congruent to the smaller triangle then we know the smaller triangle is also similar to the bigger triangle since the bigger one is also similar to the construction we made. I really think E and D is interchangeable. Choice E goes here.
