Use the equation m=y2-y1/x2-x1 to get the equation of both lines. Then, substitute numbers in to get the y-intercept. For example, for line A, you get y=4x+8. This is because 12-0/1--2 = 12/3 or 4. Then, do 12=4(1)+b. 12-4 = 8, so b equals 8. Do the same for the other line. Then, use the substitution method. This is where you take both equations and combine them without using y. For example, -2x+12=4x+8. You add 2x to 4x and get 6x. Then, you subtract 8 from 12 and get 4. We get x=4/6, which simplifies into 2/3. Then, you substitude that into one of the equations. 2/3 times 4 is 8/3 and add 8 to it. Multiply 8 by 3 to get that amount in thirds. You will get 8/3 plus 24/3 to get 32/3 as your y-value.
