Let " x "  denotes the temperature in degree Fahrenheit .
Let  " y " denotes the chirp rate per minute .
We have given that at 88 degree Fahrenheit , chirp rate is 64 times per minute and at 97 degree Fahrenheit , it is 118 times per minute .
We write this information in coordinate form ( x,y) .
We have ( x₁ ,y₁)  = ( 88 , 64 )  and  ( x₂ , y₂) = ( 97,118) .
                          y₂   - y ₁                     118  -   64                  54
Slope , m  =  ----------------------  =    ---------------------  =     -----------
                           x₂  - x₁                        97   -  88                   9
            Slope , m =  6 .
Equation of line in slope intercept form is 
y = m x + b  where  ' m' is slope and ' b ' is intercept .
Plug value of m  , we get 
y = 6 x + b .
To find value of b , we put ( 88 , 64 ) in place of x and y .
Put x = 88 and y = 64 , we get 
64 = 6 * 88 + b 
64  = 528 + b 
64 - 528 =  b 
- 464 = b 
Thus we get b = - 464 .
So the equation become 
y = 6 x - 464 .
Equation in slope intercept form representing the situation is 
y = 6 x - 464 .