I'm assuming that you mean

because if you meant

then u would simplify and you couldn't make it the subject.
Under this assumption, we start with

We multiply both sides by 

We expand the left hand side:

We move all terms involving u to the left and all terms not involving u to the right:

We factor u on the left hand side:

We divide both sides by 

<span>The answers are b = 5 square root of 3; b = -5 square root of 3. f(b) = b^2 – 75. If f(b) = 0, then b^2 – 75 ) 0. b^2 = 75. b = √75. b = √(25 * 3). b = √25 * √3. b = √(5^2) * √3. Since √x is either -x or x, then √25 = √(5^2) is either -5 or 5. Therefore. b = -5√3 or b = 5√3.</span>
Since opposite angles of a cyclic quadrilateral are supplementary,
A= 180-101=79°
B= 180-68=112°
40 common factors multiplication