alt="2(a + 5) - 3(a + 7) " align="absmiddle" class="latex-formula">
how do i simplify it
how do i simplify it
2 answers:
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9514 1404 393
Answer:
(a) -(x+7)/y
(b) (x+7)/-y
Step-by-step explanation:
There are several ways you can show expressions are equivalent. Perhaps the easiest and best is to put them in the same form. For an expression such as this, I prefer the form of answer (a), where the minus sign is factored out and the numerator and denominator have positive coefficients.
The given expression with -1 factored out is ...
Likewise, the expression of (b) with the minus sign factored out is ...
On the other hand, simplifying expression (c) gives something different.
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Another way you can write the expression is term-by-term with the terms in alpha-numeric sequence (so they're more easily compared).
Given: (-x-7)/y = (-x/y) +(-7/y)
(a) -(x+7)/y = (-x/y) +(-7/y)
(b) (x+7)/(-y) = (-x/y) +(-7/y)
(c) (-x-7)/(-y) = (x/y) +(7/y) . . . . not the same.
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Of course, you need to know the use of the distributive property and the rules of signs.
a(b+c) = ab +ac
-a/b = a/(-b) = -(a/b)
-a/(-b) = a/b
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<u>Summary</u>: The given expression matches (a) and (b).
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<em>Additional comments</em>
Sometimes, when I'm really stuck trying to see if two expressions are equal, I subtract one from the other. If the difference is zero, then I know they are the same. Looking at (b), we could compute ...
Yet another way to check is to substitute numbers for the variables. It is a good idea to use (at least) one more set of numbers than there are variables, just to make sure you didn't accidentally find a solution where the expressions happen to be equal. We can use (x, y) = (1, 2), (2, 3), and (3, 5) for example.
The given expression evaluates to (-1-7)/2 = -4, (-2-7)/3 = -3, and (-3-7)/5 = -2.
(a) evaluates to -(1+7)/2 = -4, -(2+7)/3 = -3, -(3+7)/5 = -2, same as given
(b) evaluates to (1+7)/-2 = -4, (2+7)/-3 = -3, (3+7)/-5 = -2, same as given
(c) evaluates to (-1-7)/-2 = 4, different from given
In the figure, we can consider that the base is the side that mesures 12 in and that the height is the side that measures 15 in, since that sides are perpendicular. So, we just need to use the given formula:
Hence, the area of the triangle is 90 in² (B).