Complete the square for the quadratic expression x^2 + 6x - 7.
Answer and explanation
Correct answer: C. (x + 3)^2 - 16
- Step 1: Half the coefficient of x is 6 / 2 = 3. Form (x + 3)^2 = x^2 + 6x + 9. Step 2. Subtract 9 and subtract 7: (x + 3)^2 - 9 - 7 = (x + 3)^2 - 16. Answer: (x + 3)^2 - 16. Why not the others: Failing to subtract 3^2 leaves the constant term incorrect.
Practise more Algebraic Procedures, Quadratic and Exponential Equations and Graphs.
Free questions with an explanation for every one, and full timed National Certificate of Educational Achievement mock tests.
More Algebraic Procedures, Quadratic and Exponential Equations and Graphs questions
- What are the solutions to the quadratic equation x^2 - 7x + 12 = 0?
- Simplify the algebraic fraction (x^2 - 9) / (x^2 + 5x + 6).
- What is the discriminant of the quadratic equation 2x^2 + 5x - 3 = 0, and what does it indicate about the roots?
- Express 2^(3x - 1) = 32 as a linear equation and solve for x.
- What are the coordinates of the vertex of the parabola y = (x - 4)^2 - 9?
- Solve the simultaneous equations: y = 2x + 1 and x + y = 7.