8-9n=15 I believe
At least I hope
The constant should be added to form a perfect square trinomial will be 1/4. Then the correct option is D.
<h3>What is a quadratic equation?</h3>
It's a polynomial with a value of zero. There exist polynomials of variable power 2, 1, and 0 terms. A quadratic equation is an equation with one statement in which the degree of the parameter is a maximum of 2.
The expression is x² + x.
Then the constant should be added to form a perfect square trinomial.
Then the constant will be
The square of the half of the coefficient of the variable x is to be added to make a perfect square.
Then the constant will be 1/4.
Then the perfect square will be

More about the quadratic equation link is given below.
brainly.com/question/2263981
#SPJ1
One way to do this is use the fact that the exterior angles of all polygons add up to 360 degrees
So an exterior angle of a regular octagon = 360 / 8 = 45 degrees.
So each interior angle = 180 - 45 = 135 degrees
so total measure of all angles in octagon = 8 * 135 = 1080 degrees
S is 27. SRT is 63 becuase of the vertical angles theorem. All angles of a triangle add up to 180, and you already have the other two angles. So its 27