I'm just learning algebra in school, but am having much trouble with it. My teacher makes me re-write the problems into equal expressions as well solve them. One of my many troubles is telling the difference between subtraction and a negative number. For example, here's a question in my homework that I'm struggling with:
-3x-4-5x-4-1
I get really confused with it, do I subtract or it is it negative? I notice that when numbers are next to each other it's multiplication.
I don't know, I'm being a total idiot but I need help! Thanks to everyone! (Sorry if the tag isn't the correct one, I don't know a single thing of algebra.)
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Pal
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I’m not sure if I’m understanding correctly, but I think you’re saying that you don’t know whether an expression like “$5-3$” should be read as “five minus three” or as a “five times negative 3”. If this is correct, you should read this as subtraction. Not as multiplying by a negative number. Parentheses should be used for multiplying by a negative number. For example “$5(-3)$” would be read as “five times negative three”.
Joe
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It's almost always more helpful to interpret these sorts of expressions as adding negatives. For instance, something like $x^2-3x-2a-y-5$ is best thought of as $x^2 + (-3x) + (-2a) + (-y) + (-5)$ or possibly even $x^2+ (-3)\cdot x + (-2) \cdot a + (-y) + (-5)$
TomKern
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