3r+2t=18

write the relationship as a function:
r=f(t)
evaluate: f(-3)
solve: f(t)=2​

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value

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.

thus, the first answer choice, y = sec x, is the correct one