I need help with volume equations

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I need help with volume equations

chapter 6.2

1.Find the volume V of the solid obtained by rotating the region bounded by the given curves about the specified line.

y = 7x6,  y = 7x,  x ≥ 0;about the x-axis

2.Find the volume 
V of the solid obtained by rotating the region bounded by the given curves about the specified line.

y = 3e−x, y = 3, x = 4;

about 
y = 6

3.Find the volume 
V of the described solid 
S.

A right circular cone with height 7h and base radius 4r

4.Find the volume V of the solid obtained by rotating the region bounded by the given curves about the specified line.

x = 7y2,x = 7;about x = 7