Question

Find the value of (73/10)^2-(21/10)^2 using appropriate formula​

Answer 1

Find the value of

$( { \frac{73}{10} })^{2} - ( { \frac{21}{10} })^{2}$

Solution:

Identity: (a)² - (b)² = (a+b) (a-b)

$( { \frac{73}{10} })^{2} - ( { \frac{21}{10} })^{2}$

$( \frac{73}{10} ) - ( \frac{21}{10} ) \times ( \frac{73}{10})+ ( \frac{21}{10} )$

$\frac{52}{10} \times \frac{94}{10}$

$\frac{4888}{100}$

or 48.88

Know More:

There are four standard identities. We could obtain more identities by using the standard ones:

• (a + b)² = a² + 2ab + b²
• (a - b)² = a²- 2ab + b²
• (x + a) (x + b) = x² + (a + b)x + ab
• a² + b² = (a + b) (a - b)