so Im stuck in this problem .. i don't know how they got (-1,2,0)

can someone please work this step by step

If we let z = 0, in the above system, we obtain the simpler system x+y = 3, and 3x+y = 1. The solution to the system of equations is readily calculated to be x = 1 and y = 2. Thus ( 1 , 2, 0) are the coordinates of a point on the line. Hence, a vector equation for the line is 7(t) = +t . and a set of parametric equation is X=-1 + 2t, y=2 - 14t, z=0 -4t. 3. (16pts) Find parametric equations for the line of intersections of the planes xIy4z: 3, and 3x+y2z: 1. Solution) Reference: Study Guide Question 11. Let :5] : and g =. The line of intersection of two planes is perpendicular to both planes' normal vectors )5} and r72 and therefore parallel to ] >. To nd the point on the line, we note that the coordinates (x,y,z) of any such point must satisfy the system of simultaneous equations given by the two planes x+y4z=3, and 3x+y2z= 1. 2