algebra

posted by .

What number is used to complete the square for the equation x^2 + 5x = 0?

a) 25
b) 6.25
c) 2.5
d) 10

d

  • algebra -

    (d) is not correct.

    When we need to complete the square of an expression, we examine the coefficients of the x² and x terms.

    To complete the square of a general quadratic equation
    ax²+bx+c
    we first rewrite it as:
    a(x² + (b/a)x + c/a)
    to make the coefficient of x² equal to 1.0 inside the parentheses.

    After that, we regroup the terms as
    a( (x+(b/2a))² + c/a - (b/2a)² )

    Therefore the number to complete the square is b/2 if a=1.

    Post if you need further explanations.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. math,help,algebra I

    I need help can someone help me get unstuck and let me know if i am correct.thank you. solve by completing the square. 4x^2+2x-3=0 this is what i am doing: i used the quadratic equation. so where i am is in this step: x = (-2 (+-) …
  2. algebra

    What number is used to complete the square for the equation y^2 + 16 = -y?
  3. algebra

    what number is used to complete the square for the equation y^2 + 16 = -y?
  4. algebra

    What number is used to complete the square for the equation x^2 + 5x = 0?
  5. algebra

    What number is used to complete the square for the equation x^2 = 20x?
  6. algebra

    Replace each equation with constants to complete the square and form a true equation x^2+2x+--=(x+---)^2
  7. algebra 2

    Samantha needs to solve the equation x2 - 12x = 40. What must she do to each side of the equation to complete the square?
  8. Pre-Cal

    Christian is solving the equation x2 – 12x = 4 by completing the square. What number must be added to both sides of the equation to complete the square?
  9. Algebra

    The Robertson's find that have used 1/2 gallon of paint to cover 480 square feet of wall. They used 3/4 gallon of paint to cover 720 square feet of wall. Write an equation to find the number of gallons of paint they will need (G), …
  10. Algebra

    Which of the following statements is true?

More Similar Questions