Practice30Create account

Write in the standard form .

Class 10Quadratic EquationsAlgebra — Quadratics
  • A
  • B
  • C
  • D

Step-by-Step Solution

Expand both sides: . Bring everything left: → . Choosing means you wrote 9 − 2 instead of 9 + 2 when moving −2 across. Choosing means you added and instead of subtracting. Choosing means you moved the constant but forgot to move the .
Answer: A)

Key idea: Method 2: Completing the square

Rewrite into the form .

**Steps for **:
1. Take half the coefficient of .
2. Square it: .
3. Add and subtract this value to complete the perfect square.

Example: .
→
→
→ ±2 → or −5.

Completing the square is how the quadratic formula is DERIVED. It's slower than factorisation but works ALWAYS (no clever guessing required).

Master this chapter in 30 minutes a day.

Don't just memorise the answer — build a daily practice habit.

Practice 5 Similar Questions Free →

All Quadratic Equations practice questions

More Class 10 Quadratic Equations practice

A student writes x(x − 4) + 5 = (x − 2)(x + 3) and starts hunting for the discriminant.…For which value of p is (p − 3)x² + 5x − 2 = 0 NOT a quadratic equation?Which of these values is a root of 2x² − 7x − 4 = 0?If x = −2 is a root of 3x² + kx − 2 = 0, find k.Which value of x satisfies BOTH x² − 9 = 0 and x² + 2x − 3 = 0?