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Hi!
1. -5(z^4)(-2)^3
Simplify the (-2)^3 bit first. (-2)^3 is (-2) to the power ^3 called the cube of (-2). This is -2 x -2 x -2 and 2×2x2 = 8.[x is times not ex!] Now a negative,-, times a negative gives positive (+) and - x + gives a -, So here we have - x- = + and + x - =1. So the whole thing is -.

So we have -5 x-8. This is shorthand for -5 X (z^4) x -8, As x [times] can be done in any order we will do -5 x -8 next. We now this is worth +40. So we end up with +40 x (z^4) i.e. ‘40 by z to the fourth’. By convention we can leave out the initial + sign. To work this out fully we need to know the value of z. [z is often used for complex numbers but \i assume this is not true here.]

Answer: 40(z^4)

If this is any good, and not too long winded I can go through Q2 [Ans: 2c!]

Cheers,
Brit1

OK
The answer, as I said above, is 2C. How?!

In questions like this always draw a picture. Put your variables on it. If we take this reply box let the length be L and the height be H. So the Perimeter, the distance all round is, starting at any corner, L + W +L + W or 2x{L +W} or just 2{L + W}. So P=2{L + W}
Now we are given that the perimeter is 4c + 10d. Now this can be written 2{2C + 5D}, multiply it out to make sure. Now we have found that, in any rectangle,
P =2{L + W}.

Compare the two forms-P =2{L + W},found, and P =2{2C + 5D},given. Thay must be worth the same. Now we cannot say that L=2C, it could be 5D the other being W.
However, we have been told that the width is 5d . So the length must be…what?!

Good luck!