If using the method of completing the square to solve the quadratic equation x^+15x+34=0 which number would have to be added to "complete the square"?

225x²+4=0

225x²=0-4

225x²=-4

x²=-4/225

x=±√-4/225

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:

your answer would be 12