If xy = 1, which is equivalent to x(x – 1)(y + 1)?
a) x – 1
b) x2 – 1
c) x2 – x
d) x2 – x + y – 1

B) x^2 – 1

Step-by-step explanation:

x(x – 1)(y + 1)

FOIL (x-1)(y+1)

firsy: xy

outer 1x

inner -1y

last (1)(-1) =-1

Add them together  xy +x-y-1

x( xy +x-y-1)

Replace xy with 1

x( 1+x-y-1)

x(+x-y)

Distribute

x^2-xy

But xy=1

x^2 -1

answer: sensy

step-by-step explanation:

solution:

the given function is ,

      =

the three roots of this quadratic function is , 0 ,8 and 10.all the roots are real and rational.

if a quadratic equation is of the form ,

sum of the roots = a + b +c= 0+8+10=18=  

product of roots taken two at a time = a b + b c+ c a = 0+80+0=80 =  

product of roots = a b c = 0=  

there are 11 doors in a hall starting from 0 to 11.the entry in the hall is permitted through gate number 0 and exit is allowed through only gate number 8 and 10.so, three roots(0,8,10) of quadratic function is given by entry and exit route of this hall.