Question

Find the product of -7/8 and 2/21

Answer 1

-7/8 × 2/21=-14/168

Hope it helps

Answer 2

Answer:

Required answer is $- \frac{1}{12}$

Step-by-step explanation:

Here we want to find product of $- \frac{7}{8}$and $\frac{2}{21}$

This a problem of Algebra.By fraction multiplication rule we can solve this easily.

Now, Product of $- \frac{7}{8}$and $\frac{2}{21}$

$= - \frac{7}{8} \times \frac{2}{21} = - \frac{1 \times 1}{4 \times 3} = - \frac{1}{12}$

(Here 21 was divisible by 7 and 8 is divisible by 2.So,21 and 8 were cutted by 7 and 2 respectively.)

Some important formulas of Algebra,

a + b)² = a² + 2ab + b²

(a − b)² = a² − 2ab − b²

(a + b)³ = a³ + 3a²b + 3ab² + b³

(a - b)³ = a³ - 3a²b + 3ab² - b³

a³ + b³ = (a + b)³ − 3ab(a + b)

a³ - b³ = (a -b)³ + 3ab(a - b)

${a}^{2} - {b}^{2} = (a + b)(a - b) \\ {a}^{2} + {b}^{2} = {(a + b)}^{2} - 2ab \\ {a}^{2} + {b}^{2} = {(a - b)}^{2} + 2ab \\ {a}^{3} - {b}^{3} = (a - b)( {a}^{2} + ab + {b}^{2} ) \\ {a}^{3} + {b}^{3} = (a + b)( {a}^{2} - ab + {b}^{2} )$