Question

9b-1/b^2-9 - 6b-10/b^2-9 при b=4,5

Answer 1

$\frac{9b-1}{b^{2}-9}-\frac{6b-10}{b^{2}-9} =\frac{9b-1-6b+10}{b^{2}-9} =\frac{3b+9}{b^{2}-9} =\frac{3(b+3)}{(b-3)(b+3)} =\frac{3}{b-3}$

$\frac{3}{4.5-3}=\frac{3}{1.5}=2$

Answer 2

To find the value of the expression 9b-1/(b^2-9) - 6b-10/(b^2-9) at b=4.5, we'll simply substitute b with 4.5 in the expression and perform the calculations:

Expression = (9b - 1) / (b^2 - 9) - (6b - 10) / (b^2 - 9)

Substitute b with 4.5:

Expression = (9 * 4.5 - 1) / (4.5^2 - 9) - (6 * 4.5 - 10) / (4.5^2 - 9)

Now, calculate the values:

Expression = (40.5 - 1) / (20.25 - 9) - (27 - 10) / (20.25 - 9)

Expression = 39.5 / 11.25 - 17 / 11.25

Now, find a common denominator, which is 11.25:

Expression = (39.5 - 17) / 11.25

Expression = 22.5 / 11.25

Finally, simplify the expression:

Expression = 2

So, the value of the expression 9b-1/(b^2-9) - 6b-10/(b^2-9) at b=4.5 is 2.