Help solving these math questions

Step-by-step explanation:

Given that

z³+2z²-x+x-2x+z(3z+4y²)+1-5z³+½zy²

Simplifying and opening bracket

Let open the bracket first

z³+2z²-x+x-2x+z(3z+4y²)+1-5z³+½zy²

z³+2z²-x+x-2x+3z²+4zy²+1-5z³+½zy²

Collecting like terms

z³-5z³+2z²+3z²+4zy²+½zy²-x+x-2x+1

-4z³+5z²+4½zy²-2x+1. Answer

2. 4apples+7 oranges +3apples

Collect like terms

4apples + 3apples + 7 oranges

7apples + 7 oranges

Note, we cannot add orange to apples. For example, if your dad want you to buy him 4 apples and your mum wants you to buy him 7 oranges and your brother wants you to buy him 3apples too, they all send you at the same time, you won't get to the fruit vendor and say you wants to buy 14 apples oranges or say you want to you 14 fruits, you will rather say you want to buy 7apples and 7 oranges or if you are not smart enough you will say you want to buy 4apples, 7oranges and 3apples, the seller will understand that too.

3. (x²y-3y²+5xy²)-(-x²y+3xy-3y²)

We need to know that

+×+=+. -×-=+. -×+=- +×-=-

Then let open the bracket

+(x²y-3y²+5xy²)-(-x²y+3xy-3y²)

x²y-3y²+5xy²+x²y-3xy+3y²

Collect like terms

x²y+x²y+3y²-3y²+5xy²-3xy

2x²y+5xy²-3xy.

answer: 25.4 units

step-by-step explanation: radius = 12.7 units

diameter = twice the radius

diameter = 12.7 x 2

= 25.4