All you have to do, is combine like terms. Let's go through it:

Arrange it so you can easily combine like terms:

So, your answer for the sum is 1) 7x² - 10x + 2
Answer:
19+19= x
So x, is 38. Just add 19 and 19
Answer:
Step-by-step explanation:
If you had a solid cylinder, in order to find the amount of material that makes up that solid cylinder, you would find the volume using the radius of 4 (half of the diameter 8). BUT we want to know the volume of the solid with the radius of 4 minus the solid that has a radius of 2.5 (half of the diameter 5).
That's volume outer - volume inner. To find the outer volume:
so
and
and do the same for the inner volume:
and

Subtract the inner from the outer:

If you need your answer in decimal form, then the volume is
9189.16 cm³
Total surface area = 2 * circular base + circumference * height
= 2 * pi*(4)^2 + 8pi * 12
= 32pi + 96pi
= 128pi answer