Q:

If x and p are both greater than zero and 4x^2p^2+xp-33=0, then what is the value of p in terms of x?A) -3/xB) -11/4xC) 3/4xD) 11/4x

Accepted Solution

A:
Answer:11/ (4x)Explanation:1) Make a change of variable:u = xp2) The new equation with u is:4x²p² + xp - 33 = 04(xp)² + xp - 33 = 04u² + u - 33 = 03) Factor the left side of the new equation:Split u as 12u - 11u ⇒ 4u² + u - 33 = 4u² + 12u -11u - 33Group terms: (4u² + 12u) - (11u + 33)Extract common factor of each group: 4u (u + 3 - 11 (u + 3)Common factor u + 3: (u + 3)(4u - 11).4) Come back to the equation replacing the left side with its factored form and solve:(u + 3) (4u - 11) = 0Use zero product propery: u + 3 = 0 or 4u - 11 = 0solve each factor: u = - 3 or u = 11/45) Come back to the original substitution:u = xpIf u = - 3 ⇒ xp = - 3 ⇒ x or p is negative and that is against the condition that x and p are both greater than zero, so this solution is discarded.Then use the second solution:u = xp = 11/4Solve for p:Divide both sides by x: p = 11/(4x), which is the option D) if you write it correctly.