To determine whether (−1,4) is a solution to the equation 3x+8y=29, substitute ...-1... for x and ...4... and for y.
In a pair of values like (-1, 4), the first coordinate, or entry, occupied by -1 always represents x.
Similarly, the second coordinate occupied by 4 represents y.
Answer: substitute ...-1... for x and ...4... and for y.