Can someone answer 15 and 16. i'll offer 40 points.

15.
isocoleese has 2 sides that are identical
base is not one of them
so
base+2 times sides=perimiter
10√2+2 times 12√2=P
10√2+24√2=P
34√2=P
exact value?
well, I would leave it in 34√2

16.
y=mx+b
m=slop
b=y int
given
slope=-2=m
y int is 8=b
y=-2x+8

a. y=-2x+8

b. draw the points (0,8) and (4,0) and put line thru them

c. B is the one on x axis or where y=0, so 0=-2x+8, 2x=8, x=4
the point is (4,0)

d. x intercept is where the line crosses the x axis or where y=0
that is point B or at (4,0)

If your asking how much altogether for 12 performance the answer will be 98,496.