<p>I don't understand why I am not able to solve, this is basic algebra and im a sophmore returning to this ****. </p>
<p>Solve for x: .90x + 11 = x</p>
<p>Could you explain how you get the answer?</p>
<p>thanks..</p>
<p>Also how can you tell if you subtract .9x or divide by .9x to cancel. I mean Wouldn’t both work? And why not?</p>
<p>Thanks again</p>
<p>.90x + 11 = x
11 = .10x
110 = x</p>
<p>.90x + 11 = x</p>
<p>Try this</p>
<p>.90x + 11 = x
You can express .90x as (9/10)x or 9x/10 - Same for x … 10x/10</p>
<p>Let’s pick 9x/10 and write</p>
<p>9x/10 + 11 = 10x/10
substract 9x/10 from both sides
11 = 10x/10 - 9x/10
or
11 = 1x/10
Multiply both sides by 10
and you get
110 = 1x = x</p>
<p>PS This is a much longer explanation than needed. All those steps are not necessary.</p>
<p>"Also how can you tell if you subtract .9x or divide by .9x to cancel. I mean Wouldn’t both work? And why not?</p>
<p>Thanks again "</p>
<p>what are you trying to cancel? what are you trying to find?</p>
<p>you dont divide by .9x because that would make the left side a fraction… because the 11 is still there.</p>
<p>. . .put the x’s on one side and the the numbers on the other</p>
<p>Yeah, I mean you could divide, but it’s far more pain then it’s worth. Subtracting the .9x would be much faster and the logical move to take.</p>
<p>Division would go (.222 and .111 are both repeating):</p>
<p>(.9x + 11 = x)/.9</p>
<p>x + 12.222 = 1.111x</p>
<p>(12.222 = .111x)/.111</p>
<p>110 = x</p>
<p>Fwiw, rather than divide both sides, one could multiply to … simplify the equation and get rid of the .90 or 9/10.</p>
<p>.90x + 11 = x</p>
<p>Multiply by 10 (what is easier than that 
)</p>
<p>Result is 9x + 110 = 10x
and 110 = 10x - 9x = 1x</p>
<p>I’ve also heard that if you bring your lucky cricket with you to the SAT it will land on all the correct answers.</p>
<p>I’m pretty sure that collectively we’ve over-solved this problem…</p>
<p>This would also be a good time to use the solve command on the TI89:</p>
<p>Solve(.9x+11=x,x)</p>
<p>And yes I know: you don’t NEEEEEED a TI89 to score 800+ on the SAT. But lots of people who take this test are not completely fluent in algebra. The TI89 offers another path to the answer.</p>
<p>Thanks I got it now. Now I think I will have elementary algerbra down if someone could explain this problem. </p>
<p>Solve for w: K = 917 + 6(w + h - a)</p>
<p>Now why can’t the answer be w = (K / 6) - 917 + a - h
Why must it be w = (K - 917 / 6) + a - h
?</p>
<p>I’m getting my answer [to differ] by taking the following steps:</p>
<h1>1: First dividing both sides by 6.</h1>
<h1>2: Then subtracting 917</h1>
<p>Thanks again, you guys were really helpful.</p>
<p>When do you divide both sides by 6, you also have to divide the 917 by 6.</p>
<p>But when you divide by 6, don’t you have to divide h and -a as well as 917?</p>
<p>Why!!?</p>
<p>K = 917 + 6(w + h - a)</p>
<p>If you distributed the 6 the equation would be
k = 917 + 6w + 6h - 6a
so if you divided everything by 6 it would be
k/6 = 917/6 + w + h - a </p>
<p>So if you get confused by the parentheses just distribute and solve normally.</p>
<p>No, because of the distributive property. The 6 is outside of the parenthesis.</p>
<p>If you distribute the original equation, you get:
K = 917 + 6w + 6h - 6a</p>
<p>Then by your method of dividing by 6, you get:
K/6 = (917/6) + w + h - a</p>
<p>(K/6) - (917/6) - a + h</p>
<p>Edit: Took a little longer to post than Jshapiro, but you should get the idea now. Also, if you need help with basic algebra, try searching google for those free out of print algebra e-textbooks. Or you could try finding some books at your local library/book store.</p>
<p>How the hell did I not get that, its so friggen easy. Thanks again</p>
<p>Do you think this stuff is important enough for calculus that I get a book on problem solving?</p>