8. if a and b are non-empty sets we define their cartesian product a x b as follows: a, b) a e a and b e b that is, ax b is the set of all ordered pairs with elements of a in the first slot and elements of b in the second slot produce a function f : n x n n which is injective.

according to the triangle sum theorem, all the angles in a triangle must add up to 180 degrees. if we know one angle is already 90, we do 180-90=90. the other 2 angles must add up to 90, exactly.

step-by-step explanation:

the formula for the equation of a circle is (x – h)2+ (y – k)2 = r2, where (h, k) represents the coordinates of the center of the circle, and r represents the radius of the circle. if a circle is tangent to the x-axis at (3,0), this means it touches the x-axis at that point.