<span>Differentiating :
y' = 1 + sec^2(x),
</span><span>
cosπ=−1</span><span>
plug in pi = -1 ,for x:
1 + sec^2(pi) = 1 + (-1)^2
= 2</span>
If it can scan 72 photos in 8 minutes, it can scan 72/8 = 9 photos per minute.
So in 23 minutes, it can scan 9x23 = 207 photos
Answer:

Step-by-step explanation:

Move 3k to left hand side and change it's sign
Similarly, move 4.5 to right hand side and change it's sign

Collect like terms

Subtract 4.5 from 18

Divide both sides by 4.5

Calculate

Hope I helped!
Best regards! :D