Here's the question you clicked on:
d_poole
x(7 – x) > 8 A. 2 B. 8 C. –1 D. 0
Start by distributing that x. x(7 -x) > 8 7x + x^2 > 8 x^2 + 7x -8 > 0 (x+8)(x-1) > 0 x = -8 x = 1
Then substitute each back into the original equation, and see which one is true.
For a problem like this, that you don't know how to solve, it is best to just pluge in the answers. A 2= 10>8 B 8= -8>8 C -1= -8>8 D 0= 0>8 So there is only one true statement there and it is a
where did the 10 come from?
@Rosy95: there will be an occasion when there are no answers... Therefore, it is always better to learn how to do such a problem (see @blurbendy's method), so next time you'll know what to do.
10 is what you get on that side when you sub the 2 in for the x's. x(7-x)>8 2(7-2)>8 14-4>8 10>8 @ZeHanz yes I know that, however I was just saying that when it comes down to a test you cant just look it up, therefore when they give you answer choice, plug it in
@Rosy95: Am I right in thinking that a lot of people asking questions here do multiple choice questions all the time?
Yes, and on math test it is a lot of mult choice questions, so if you are not getting something, plug it in and your welcome @d_poole
That explains a lot. I'm from Holland, and many high school students never see even one multiple choice question at maths.
Oh ok. Well to give you an example. I had a 40 question math test and only 3-5 were NOT multipul choice, so even if you miss the written ones, you will still pass.
Advantage for the teacher: quick grading, although less rewarding if students are just trying some numbers, probably using a calculator...
yes that is all true lol...and I am actually a tutor in algebra currently so I know how do these problems, but because someone had already explained how to do this problem, i was giving d_poole another option
but @ZeHanz if you are good at precal or math in general can you help me with my question..here is the link to it on here http://openstudy.com/study#/updates/50f5c9aee4b061aa9f9ad656
I'going to sleep now...sorry, but glad to help you soon! Bye.