Answer:
a₁ = - 24
Step-by-step explanation:
The n th term of an AP is
= a₁ + (n - 1)d
where a₁ is the first term and d the common difference
Given a₇ = 2a₅ , then
a₁ + 6d = 2(a₁ + 4d) = 2a₁ + 8d ( subtract 2a₁ + 8d from both sides )
- a₁ - 2d = 0 → (1)
The sum to n terms of an AP is
= 
[ 2a₁ + (n - 1)d ]
Given 
= 84 , then
(2a₁ + 6d) = 84
3.5(2a₁ + 6d) = 84 ( divide both sides by 3.5 )
2a₁ + 6d = 24 → (2)
Thus we have 2 equations
- a₁ - 2d = 0 → (1)
2a₁ + 6d = 24 → (2)
Multiplying (1) by 3 and adding to (2) will eliminate d
- 3a₁ - 6d = 0 → (3)
Add (2) and (3) term by term to eliminate d
- a₁ = 24 ( multiply both sides by - 1 )
a₁ = - 24
X=-263/10 which is also the root to the equation.
Answer:
After 4 movies it will be equal
Step-by-step explanation:
10x + 160 = 50x
160 = 40x
4 = x
Check:
10x + 160 =
10(4) + 160 =
40 + 160 = 200
50x =
50 x 4 = 200
200 = 200
Okay so process of elimination. The first option isn't correct because the sum of the interior angles for any triangle is always 180 degrees. x would be 25 degrees for ABC because 90+65=155 and 180-155=25. Y would be 95 degrees for DEF because 65+20=85 and 180-85=95, so y does not equal 90 degrees. For B, No side lengths are given. C is also not the correct answer so the answer is D. I can link you to another brainly post that has the same question or a similar with an explanation on determining the answer if you'd like :)
