Question

solve and verify [-1/4a+1/5b] [1/4a+1/5b] ; a=8 and b =5​

Answer 1

Step-by-step explanation:

Given:

$( - \frac{1}{4a} + \frac{1}{5b} )( \frac{1}{4a} + \frac{1}{5b})$

To find: Solve and verify for a=8 and b=5

Solution:

We know that

$(x + y)(x - y) = {x}^{2} - {y}^{2}$

So,

$( - \frac{1}{4a} + \frac{1}{5b} )( \frac{1}{4a} + \frac{1}{5b}) \\ \\=>\bigg ( \frac{1}{( {5b)}^{2} } \bigg) - \bigg( \frac{1}{( {4a)}^{2} }\bigg ) \\ \\ = > \frac{1}{25 {b }^{2} } - \frac{1}{16 {a}^{2} }$

Put the value of a and b

$\frac{1}{25 {(5) }^{2} } - \frac{1}{16 {(8)}^{2} } \\ \\ = > \frac{1}{25 \times 25} - \frac{1}{16 \times 64} \\ \\ = > \frac{1}{625} - \frac{1}{1024} \\ \\ = > 0.000623$

Hope it helps you.