7. Three planes can intersect in a number of different ways. For each of the combinations below, find the single point of intersection if there is one. If there isn't, explain how the planes do intersect. 7 1 : 3x + 4y + 2z -1 = O a. 712 : -2x + 5y + 3z +7 = 0 713 : 5x + 4y + 2z - 3 = 71 : x - 2y + 3z-1 = O b. 72 : -3x + 5y + 2z+7 = O 73 : -x+y+8z+5 = 8. Give the equations of three planes that meet in three lines. Explain your reasoning and include a LanGraph of your planes that allows you to see the triangular prism created