<p>wuts up guys? </p>
<p>I'm having trouble understanding a question, maybe u could help me out?</p>
<p>3(x-7)(x-2)=k
In the equation above, k is a constant. If the roots of the equation are 7 and 2, what is the value of k?</p>
<p>I mean wut r they asking for? The roots r 7 and 2, but k depends on wut I put in for x... they dont say anyting about x though... I dont understand wut they want...</p>
<p>isn't k=0? ...if you have something like (x-7)(x-2)=0, you set (x-7)=0 and solve for x. An you do the same for (x-2).</p>
<p>but it doesnt say anthing about setting the equation to zero... it just says: If the roots of the equation are 7 and 2, what is the value of k?but the roots dont tell us anything about the x value...</p>
<p>the roots of a quadratic equation, the type of equation you're given, are the values of x that make the equation equal to 0.</p>
<p>By this definition, it makes sense that the roots would be 7 and 2 because 3(7-7)=0 and 3(2-2)=0. In this case, k would be equal to 0</p>
<p>But then again, all quadratics are solved by setting them equal to zero and then factoring or using the formula. I've never seen a question like this and it certainly doesn't look like one that would appear on the SAT. Sorry if this doesn't help.</p>
<p>yea... I still appreciate ur help...
this question is from the official sat online course, and I've never anything like this before, so basically the question is incomplete, imo... but wut do I kno, ^^...
but if u look at the question, is just says that 7 and 2 are the roots of the equation, thats it. so k could only be expressed in terms of x, but they only give u numbers for k, so its very confusing</p>
<p>What are the answer choices?</p>
<p>0
2
3
7
14</p>
<p>The answer should be zero.</p>
<p>If it's a root, then when you plug it back into the equation, it equals zero, that's what a root means.</p>
<p>3(x-7)(x-2)=k</p>
<p>3(7-7)(7-2)=k
3(0)(5)=k
0=k</p>
<p>3(2-7)(2-2)=k
3(-5)(0)=k
0=k</p>
<p>So k is a constant with both roots.</p>
<p>so there you have it. The answer is zero.</p>
<p>thats wut I thought, but if u read the questions carefully it just says:
"If the roots of the equation are 7 and 2, what is the value of k"... it doesnt say that ur suppossed to plug in the roots, or do anything with the roots at all. It doesnt say that u have to plug them back in, it just says wut the roots are, which u can infer from seeing the equation. the problem is, imo, that the question is incomplete. I mean the roots of the equation r always gonna be 7 and 2, but, k depends on wut u plug in for x, and it doesnt say anything about x... I've never seen a question like this, and I think they phrased the questions wrongly...</p>
<p>if the question is incomplete the choice E would be: cannot be determined from the information given.
which it is not, so the question is complete but we just can't crack the code.
why not just send an e mail to the CB and ask them. doesn't the online course have answer explanations?</p>
<p>the only logical answer is zero. </p>
<p>((WOOOOW!!!!! THIS IS MY 600TH POST!!!!!!!!!))</p>
<p>yes it has answer explanations, but I'm doing an extreme untimed sat test, and I havent finished it yet, so I cant access the answers yet...</p>
<p>hey congrats man, 600 is awesome</p>
<p>
[quote]
"If the roots of the equation are 7 and 2, what is the value of k"... it doesnt say that ur suppossed to plug in the roots, or do anything with the roots at all. It doesnt say that u have to plug them back in, it just says wut the roots are, which u can infer from seeing the equation. the problem is, imo, that the question is incomplete. I mean the roots of the equation r always gonna be 7 and 2, but, k depends on wut u plug in for x, and it doesnt say anything about x... I've never seen a question like this, and I think they phrased the questions wrongly...
[/quote]
</p>
<p>k is a constant, meaning it stays the same.
Think about it, what other values can you plug in so that k remains constant?
The problem gave you the roots so you DIDN'T have to find other values to plug in and guess and check for all of eternity.</p>
<p>I agree, but they should rephrase their questions, becos thats not wut the instructions r telling u...</p>
<p>So is the answer zero? Assuming you're done I mean.</p>
<p>
[quote]
I agree, but they should rephrase their questions, becos thats not wut the instructions r telling u...
[/quote]
</p>
<p>All the information is given, you're suppose to "reason" (SAT 1: Reasoning Test) your way to the answer.</p>
<p>um... i hope its 0, we'll see when i enter the answers online</p>