#1 and 12 question on 16

For number one I created two equations one for the point (-2,8) and another for the point (4,-6). Then I added these two equations together and this canceled out K, leaving me with the value for m: -14/3. Then I plugged this back into one of the original equations to find the value for K: -3.333. So k+m is -3.333 + -14/3 which is -8.

For number 12, the equation of a parabola is ax^2+bx+c And so we can find a b and c by plugging in points from the graph into equations and then solving for them. To find C i plugged in 0,-2 which took A and B out of the equation leaving C which when solved for is -2. Then after that I plugged -2 into the equation again along with the point -2,-3. There I solved for B in terms of A to get B= 2a+.5 Finally I plugged that in for B along with the C value and point 1,0 ans solved for A and then used that value of .5 to solve for B giving me a final equation of .5x^2+1.5x+(-2)

Can someone post another solution to 16