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
Answer:
x=1
Step-by-step explanation:
multiply both sides by 28 (it is the Least Common Multiple) which would bring your equation to be
7x-2= 4x+1
3x=3
x=1
We need the circumference and area of the circle equations:
c = 2*pi*r
a = pi*r^2
lets find the radius from the first equation:
r = c/2*pi
r = 157/(2*3.14)
r = 24.99 ft
now lets calculate the area:
a = pi*r^2
a = 3.14*(24.99)^2
a = 1960.93 ft^2
Now we need to divide the total area by the rate at which Chris paints, and that gives us the time needed:
time = <span>1960.93/400
time = 4.9 hours
that would be 5 hours rounded to the nearest hour</span>
Answer:
1l
Step-by-step explanation:
5n
