The way to do this easily is to first determine the equation for your particular situation. Yesterday she read 75 pages, so that 75 pages is our starting point today, plus 2 pages per minute which is expressed as 2x. So our equation is y=2x + 75. The table with the negative x value...forget it. The two things in math that will NEVER be negative are length/distance and time, so no negative x values allowed. From the first table, after 2 minutes of reading, our equation would be y = 2(2) + 75 and y = 79. So far so good, but let's try another x value just in case. After 14 minutes of reading, our equation is y = 2(14) + 75 and y = 103. Not the y value from the table. So that's not it either. Moving down we go to the third table. After 0 minutes of reading, we KNOW we haven't read 0 pages because yesterday we read 75. So if x = 0, then y has to = 75. So that's not it either. We're running out of possibilities. The last table gives us x = 0 and y = 75, so we already know that's right. After 11 minutes of reading, y = 2(11) + 75 and y = 97. Ok, one more. After 20.25 minutes, y = 2(20.25) + 75 and y = 115.5. The last table is our choice.
