<p>In the xy plane ,the graph of the function f is a line.If f(2) = 7 ,and f(12) = 1 , what is the value of f(7)</p>
<p>given points (2,7) and (12,1)</p>
<p>write the equation of the line and plug in 7…</p>
<p>You have (2, 7) and (1, 12) so the slope is -5
7 = -5(2) + b
b = 17
so y = -5x + 17
(f7) = -5(7) + 17 = -18</p>
<p>The answer is 4 ,and this question is from the May 06 test.</p>
<p>EDIT :Immortalix,i think your answer is wrong because the point is (12 , 1 ) ,not (1,12) ,and therefore the slope is -6/10 = -3/5</p>
<p>I got 4.</p>
<p>First take your points (2,7) & (12,1)
The slope is -6/10 or -3/5</p>
<p>Plug that into the functions to find (b)</p>
<p>f(2) = 7</p>
<p>7 = -3/5(2) + b</p>
<p>b = 8.2</p>
<p>So f(7) = -3/5(7) + 8.2</p>
<p>So f(7) = 4</p>
<p>you could notice that 7 is exactly half way between 2 and 12
so the y should be the average of the function values
hence 4</p>
<p>This is an easy problem. Its just a midpoint calculation don’t overcomplicate it.</p>
<p>(12 + 2)/2 = 7</p>
<p>so</p>
<p>(7 + 1)/2 = 4</p>
<p>I didnt get it 4.0
(x1+x2)/2 and (y1+y2)/2 is the mid point of a line.</p>
<p>Why (7+1)/2 =4</p>
<p>if you notice, they want you to find the y value at 7. It just so happens that x=7 is the midpoint of the line. If this is the case, then you can do the same thing for the y values.</p>
<p>Points are (2,7) and (12,1)
Therefore slope equals -3/5
Your equation of the line is 7=-3/5(2) + b
b = 8.2 y=-3/5x + 8.2
Answer is 4.</p>