Factor using the AC method...
The answer is:
(x+6) (x+8)
The surface area of a sphere is 4r^2pi, so dividing 100 by 4pi gives a result of 25/pi. Taking the square root and rationalizing the denominator, we have 5sqrt(pi)/pi as the radius of the sphere.
The only values a cosine can have are from -1 to 1.
(x,y)
(2,1)
sub 2 for x and 1 for y and see if you get a true statemtn
2=x
y=1
1=1-2
1=-1
false
no it is not a soluiton