<p>Can somebody kindly explain numbers 41 and 42 from the Math level 2 test in the official College Board book for all the subject tests? It's on page 203 and 204 and have no idea about either. Thank you in advance!</p>
<h1>41: to find graph fg, you just look at the corresponding y values for each x value on each of the graphs. you can immediately eliminate B because we know fg has to pass through the origin because 0x0 = 0. Then basically, you see that when x > 0, f is positive and g is negative, which results in a negative number; you also see that when x < 0, f is negative and g is positive, which is a negative. therefore, the graph fg has to have a point at the origin and be negative for all other x values. only choice A satisfies these conditions</h1>
<h1>42: the square root of any number will always give a positive. therefore, we know if -x is going to equal the positive number, it would have to be a negative number because the double negative will cancel out to make the positive.</h1>
<p>hope that helps!</p>
<p>Thanks for your quick response it helped a lot 
But for #42 why can’t zero be a possible answer? is it because zero is neither positive nor negative…</p>
<p>yeah, that seems to be right, I guess you can’t really consider the zero to be either positive or negative</p>