It took them 4 days to install 480 chairs which means if they were working at a constant rate they got 120 chairs installed daily. with 360 chairs left that means in 3 days they will finish. so overall, it took the workers 7 days to finish, or a week.
The pictures too blurred, can you write it out?
1. n^2 -8n +16 = 25
Subtract 25 from both sides
n^2 - 8n + 16 - 25 = 0
Simplify
n^2 - 8n - 9 =0
Factor
(n-9)(n+1) = 0
Solve for n
n-9 = 0, n = 9
n+1 = 0, n = -1
Solution: 9,-1
2. C = b^2/25
Multiply both sides by 25:
25c = b^2
Take square root of both sides
b = +/-√25c
Simplify:
b = 5√C, -5√C
3. d = 16t^2 +12t
subtract d from both side:
16t^2 + 12t -d =0
Use quadratic formula to solve:
t = (3 +/-√(9-4d))/8
4. 5w^2 +10w =40
Subtract 40 from both side:
5w^2 + 10w -40 = 0
Factor:
5(w-2)(w+4)=0
Divide both sides by 5:
(w-2)(w+4)=0
Solve for w:
w-2 = 0, w = 2
w+4=0, w = -4
Solution: 2,-4
