What does the quadratic function y=x2−10x+9 look like when rewritten in the form f(x)= a(x-h)^2 +k?

Statements reasons 1. ab ? cd; ad ? bc 1. given 2. ac ? ac 2. reflexive property 3. ? adc ? ? cba 3. ? 4. ? dac ? ? bca; ? acd ? ? cab 4. cpctc 5. ? dac and ? bca are alt. int. ? s; ? acd and ? cab are alt. int. ? s 5. definition of alternate interior angles 6. ab ? cd; ad ? bc 6. converse of the alternate interior angles theorem 7. abcd is a parallelogram 7. definition of parallelogram what is the missing reason in step 3?

Asinusoidal function whose frequency is 1/6pi

Typically a point in a three dimensional cartesian coordinate system is represented by which of the following answers in the picture !