Algebra I Quiz Solutions

Some helpful information:
point-slope form: y = y1 + m(x - x1)
slope-intercept form: y = mx + b
slope formula: m = (y2 - y1)/(x2 - x1)

1) Use two points in the table to calculate the slope: (3, 12) and (7, 24). m = (24 - 12)/(7 - 3) = 12/4 = 3. Use any point to write the equation in point-slope form. (3, 12). y = 12 + 3(x - 3)

2) Use the points on the graph to count the slope. From the first to the second point (left to right), I count up 2, right 1, which gives me the slope 2/1 = 2. The y-intercept is at 2, so my equation in slope-intercept form is y = 2x + 2.

3) Same process as #2. The slope is counted down 3, right 2, which gives me a slope of -3/2 = -1.5. The y-intercept is 6, so my equation is y = -1.5x + 6.

4) Use the slope formula: m = (-4 - -1)/(9 - -4) = (-4 + 1)/(9+4) = -3/13

5) m = (-4 - 4)/(-4 - 3) = -8/-7 = 8/7

6) m = (0 - 0)/(1 - 0) = 0/1 = 0