In your question, 45 is not a perfect square. A perfect square is when you divide or multiply the number by itself. 36 is a perfect square because it's factor is 6 x 6 (6,6). <span>64 is a perfect square because it's factor is 8 x 8 (8,8). </span><span>81 is a perfect square because it's factor is 9 x 9 (9,9).</span>
Equation of a line through two points is given by y - y1 = ((y2 - y1)/(x2 - x1))(x - x1) y - (-1) = ((5 - (-1))/(4 - 2))(x - 2) y + 1 = ((5 + 1)/2)(x - 2) y + 1 = 6/2 (x - 2) y + 1 = 3(x - 2) = 3x - 6 -3x + y = -6 - 1 -3x + y = -7