Which expression represents the value of x in the equation dx+e=f

Me what is the value of x? showing work would be appreciated - ! : )

Asap for seven months an ice creams vendor collects data showing the number of cones sold a day (c) and the degrees above 70 degrees f the vendor finds that there is a positive linear association between c and t that is the best modeled by this equation c=3.7t+98 which statement is true? the model predicts that the average number of cones sold in a day is 3.7 the model predicts that the average number of cones sold i a day is 98 a model predicts that for each additional degree that the high temperature is above 70 degres f the total of number of cones sold increases by 3.7 the model predicts for each additional degree that the high temperature is above 70 degrees f the total number of cones sold increasingly by 98

Which math sentence can be used to determine if the triangle is a right triangle?