Not sure I want to get in the middle of this, but, literally, I'm in the middle of this. I consider myself a realist and teach students both methods. Admittedly, I strongly urge students to learn the math, do the math accurately and learn why something is correct mathematically. I really feel that it has the biggest payoff on test day.
However, I'm a realist and will expose my students to backsolving techniques so that on test day, when they're staring at the screen and the algebra escapes them, they have something to lean on. Like Ian, I believe that elite scores go to those who do the math quickly and accurately.
I think it is akin to Sentence Correction questions. Eliminations strategies are better than nothing, but the best scores go to those students with a strong command of grammatical and idiomatic rules.
2 min question again :)
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VP_RedSoxFan
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Ryan S.
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Ian Stewart
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Don't mean to start anything serious here(!)- I only hope to have a good-natured discussion of how to best succeed on the test.VP_RedSoxFan wrote:Not sure I want to get in the middle of this, but, literally, I'm in the middle of this.
I think the advice above is the best advice for the GMAT. I teach backsolving as well, but as a fallback strategy, not as a first port of call.VP_RedSoxFan wrote: I consider myself a realist and teach students both methods. Admittedly, I strongly urge students to learn the math, do the math accurately and learn why something is correct mathematically. I really feel that it has the biggest payoff on test day.
However, I'm a realist and will expose my students to backsolving techniques so that on test day, when they're staring at the screen and the algebra escapes them, they have something to lean on. Like Ian, I believe that elite scores go to those who do the math quickly and accurately.
I think it is akin to Sentence Correction questions. Eliminations strategies are better than nothing, but the best scores go to those students with a strong command of grammatical and idiomatic rules.
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AleksandrM
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athinabean
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area of walkway = (3x+5)^2 - (x+5)^2 = 132
solving we get x = 3
Can somebody please show me how you got x=3 from the above? I cannot do ir for some reason and it is driving me crazy.
thanks.
solving we get x = 3
Can somebody please show me how you got x=3 from the above? I cannot do ir for some reason and it is driving me crazy.
thanks.
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Ian Stewart
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Note that the left side is a difference of squares: a^2 - b^2 = (a+b)(a-b).athinabean wrote:area of walkway = (3x+5)^2 - (x+5)^2 = 132
solving we get x = 3
Can somebody please show me how you got x=3 from the above? I cannot do ir for some reason and it is driving me crazy.
thanks.
So,
(3x+5)^2 - (x+5)^2 = 132
[(3x + 5) + (x + 5)][(3x + 5) - (x + 5)] = 132
(4x + 10)(2x) = 132
8x^2 + 20x = 132
2x^2 + 5x - 33 = 0
(2x + 11)(x - 3) = 0
x = 3, -5.5
Discard the negative solution; distances can't be negative.
