Question

78² − 22² = ______.

Options

• 5,600

• 6,600

• 5,700

• 5,900

Answer 1

78² − 22² = 5,600.

Explanation:

a² − b² = (a + b) (a − b)

= (78 − 22) (78 + 22)

= 56 × 100

= 5,600