y = a + b / x where a , b are real numbers, if y = 1 when x = -1 and y = 5 when x = -5, then a +b equals

a. -1 b. 0 c. 11 d . 10

Question

y = a + b / x where a , b are real numbers, if y = 1 when x = -1
and y = 5 when x = -5, then a +b equals
a -1 b 0 c 11 d 10

Aakash Sharma · Accepted Answer

$Given: y = a + \frac{b}{x} \Rightarrow x y = a x + b Now when x = - 1, y = 1 \Rightarrow - 1 = - a + b \Rightarrow a - b = 1 ... (1) and when = x - 5, y = 5 \Rightarrow - 25 = - 5 a + b \Rightarrow 5 a - b = 25 ... (2)$

Subtracting (1) from (2) we get

$4 a = 24 \Rightarrow a = \frac{24}{4} = 6$

putting the value of a in (1) we get

b = 5

∴ a + b = 6 + 5 = 11

y = a + b / x where a , b are real numbers, if y = 1 when x = -1 and y = 5 when x = -5, then a +b equals a. -1 b. 0 c. 11 d . 10

y = a + b / x where a , b are real numbers, if y = 1 when x = -1 and y = 5 when x = -5, then a +b equals

a. -1 b. 0 c. 11 d . 10