If x = √45 + √5, then what is the value of x²?
Show answer & explanation
Correct answer: B
Explanation
Given:
x = √45 + √5
According to the formula:
(a + b)² = a² + b² + 2ab
x² = (√45 + √5)²
= (√45)² + (√5)² + 2√45√5
= 45 + 5 + 2√(45 × 5)
= 50 + 2√225
= 50 + 2 × 15
= 50 + 30
= 80