Hey Whoever help me i will mark brainliest King or queen

Which statement justifies why angle ebc measures 90?

Graph g(x)=2cosx . use 3.14 for π . use the sine tool to graph the function. graph the function by plotting two points. the first point must be on the midline and closest to the origin. the second point must be a maximum or minimum value on the graph closest to the first point.

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