<span>The greatest common factor of two or more numbers is the greatest common factor of the two or more numbers that can divide the numbers without remainder. Factors of 60x^4y^7, 45x^5y^5 and 75x^3y.
60x^4y^7 = 2, 2, 3, 5, x, x, x, x, y, y, y, y, y, y, y
45x^5y^5 = 3, 3, 5, x, x, x, x, x, y, y, y, y, y
75x^3y = 3, 5, 5, x, x, x, y
The common factors are 3, 5, x, x, x, y = 15x^3y (the second option). </span>
Parallel lines need to have the same slope. Lines red and green both have a slope of 1/2.
The slopes of two lines that are perpendicular have to be opposite reciprocals, and must be multiplied together to get -1. Line black has a slope of -4, and line blue has a slope of 1/4. Both of them multiplied together equals -1.