Alan

This is \(\frac{5}{6i}\rightarrow \frac{5i}{6i^2}\rightarrow -\frac{5i}{6}\rightarrow0-\frac{5i}{6}\)

Distance past line by A after time t hours = 65t km

Distance past line by B after t hours = 70*(t - 10/3600) km (10 seconds = 10/3600 hours)  This assumes B is travelling at 70 km/h for the 10 seconds before passing the line.

When these are equal:

70(t - 10/3600) = 65t

70t - 700/3600 = 65t

5t = 700/3600

t = 700(3600*5) hours or t = 700/5 seconds or t = 140 seconds

...

Do you mean 2x² or (2x)² → 4x² or 2x times something to the power 2?

Do you mean sin^-1(x) = 0.389?  If so x = sin(0.389), and it is likely that the 0.389 is radians (0.389 radians = 22.3°), so that x = 0.3793

The only way to find out is to post a specific question!

Here's the first one answered for you.  Let's see if you can use this to help you answer the others.

Two hundred and nine thousand one hundred divided by two hundred and four!

Good try Guest, but the question specifies that the perimeters are the same, not the areas!

Perimeter of square:  4x

Perimeter of rectangle: 2*(2x-4) + 2*(x-6) = 4x - 8 + 2x - 12 = 6x - 20

So 4x = 6x - 20

2x = 20

x = 10 cm

Perimeter of square = 4*10 = 40 cm

Perimeter of rectangle = 6*10 - 20 = 60 - 20 = 40 cm

Just type it into the calculator exactly as you have written it:  1/3