Math Problem Statement

By first writing the left-hand side of the identity in completed square form, work out the value of m.

Solution

We are tasked with completing the square for the quadratic expression 2x220x+m2x^2 - 20x + m and using that to match it with the form p(xq)2+3qp(x - q)^2 + 3q, which will allow us to find the value of mm.

Step-by-Step Solution:

  1. Factor out the leading coefficient (2): The expression is 2x220x+m2x^2 - 20x + m. We factor out the 2 from the terms involving xx: 2(x210x)+m2(x^2 - 10x) + m

  2. Complete the square inside the parentheses: To complete the square, we look at the x210xx^2 - 10x term. Take half of the coefficient of xx (which is 10-10), square it, and add and subtract it inside the parentheses: x210x=(x5)225x^2 - 10x = (x - 5)^2 - 25 So the expression becomes: 2((x5)225)+m=2(x5)250+m2((x - 5)^2 - 25) + m = 2(x - 5)^2 - 50 + m

  3. Rearrange the expression: Now we rewrite it as: 2(x5)2+(m50)2(x - 5)^2 + (m - 50)

  4. Compare this with the given form: The given form is p(xq)2+3qp(x - q)^2 + 3q. From this, we see that: p=2,q=5,and3q=m50p = 2, \quad q = 5, \quad \text{and} \quad 3q = m - 50 Substituting q=5q = 5 into 3q3q, we get: 3(5)=m5015=m503(5) = m - 50 \quad \Rightarrow \quad 15 = m - 50

  5. Solve for mm: Add 50 to both sides: m=65m = 65

Thus, the value of mm is 65.

Would you like more details or clarifications on any step?

Related Questions:

  1. How do you complete the square for a quadratic expression?
  2. Why do we factor out the leading coefficient before completing the square?
  3. What is the general formula for completing the square?
  4. How does completing the square help in solving quadratic equations?
  5. What are other methods to solve quadratic expressions, apart from completing the square?

Tip:

Completing the square is also useful in finding the vertex of a quadratic function, as the expression a(xh)2+ka(x-h)^2 + k gives the vertex (h,k)(h, k).

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Math Problem Analysis

Mathematical Concepts

Algebra
Completing the Square
Quadratic Equations

Formulas

ax^2 + bx + c = a(x - h)^2 + k
p(x - q)^2 + 3q = Quadratic form for matching

Theorems

Quadratic Identity Matching
Completing the Square Method

Suitable Grade Level

Grades 9-11