Which point is an x-intercept of the quadratic function f(x)=(x+6)(x-3)

The coordinates r(1, -3), s(3, -1) t(5, -7) form what type of polygon? a right triangle an acute triangle an equilateral triangle an obtuse triangle

Which expression is the factorization of x^2+10+21

What is the simplified form of square root of 400 to the 100th power ?