Answer:
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Use the slope-intercept form to find the slope and y-intercept. To do this, use y=mx+b. Plug the variables where m=1 and b=2. Slope of the line is m and y-intercept is value of b, so the slope is 1 while the y-intercept is (0,2). Any line can be graphed using two points, and using two x values to plug them into the equation to find the corresponding y values: 0=x+2 is (-2,0). Y-intercept is already known, so use the known values and make a table where x= -2,0 and y = 0,2. Now, graph the line using the slope, y-intercept, and known points (-2,0), (0,-2) to plot the graph. Coincidingly, the answer to solve your system of equations will be the x-intercept: (-2,0).
If her second test was x and her third was x+1 (since it was 1 more than the second), we get 75+x+x+1=76+2x as our total test scores. Next, to get the average you add up the numbers and divide it by the amount of numbers you have. Since we have 3 tests and our sum is 76+2x, we divide it by 3 to get (76+2x)/3=average=82. Multiplying both sides by 3, we get 246=76+2x. Next, we subtract both sides by 76 to get 170=2x. Lastly, we divide both sides by 2 to get 85=x= the second test score. Her third test score is x+1=85+1=86