What is the standard equation of a line whose x- and y-intercept are 5 and 3, respectively?

What is the value of x in the this question ?

The number of 8th graders who responded to a poll of 6th grade and 8 th graders was one fourtg of the number of 6th graders whi responded if a total of 100 students responddd to the poll how many of the students responded were 6 th graders

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