Line L passes through point (1,4) and the product of its

Sorry to be the 'dumb blonde' but could you explain?

Thank you!

You are right, the oa is (5,7).

Now I have to try to get it right!

I dont see why I did that, but still I took the slope for each of the cases,

ie. (y2 - y1)/ (x2 - x1)

For all except B, I got a negative slope.

Since B was the only different one, I selected B.

But can someone please explain why the slope has to be positive?

remgeo,

if you see my post above i have derived why slope has to be positive .

the slope has to be B^2 and obviously that will always be positive .

Thanks.

I selected B.

I just drew out an xy graph and put a dot on (1,4). From there, I knew that the product of the x intercept and y intercept needed to be negative.

So I went down through the answer choices and looked for a line that crossed either the x or the y axis at a negative point.

(A) Doesn't work because when you draw the line, the x and y intercepts are both positive. Hence when you multiple them, the number will be positive. If you want to solve it out, the x intercept here would be (5,0). The y intercept would be (0,5). When you multiply, the ans is positive.
(B) When you plot this point and draw a line that goes through (1,4), you will see a negative slope. The y intercept is positive, but if you keep tracing the line, it crosses the x axis at a negative point. When you multiply the two products, the number will be negative. B is correct.
(C) Same situation as A
(D) Same situation as A. Despite the negative number, the x intercept is still positive.
(E) Same situation as A. Despite the negative number, the x intercept is still positive.

Answer is B...

I found drawing the graph easier than solving it using y=mx+c!

Agree with B :wink: