Question

How to solve for these

Answer 1

9514 1404 393

Answer:

1. f = 9/a +7

2. x = (y -5)/3

3. x = 3/(y +2)

4. l = (P +9)/4

Explanation:

I find it convenient to use the fact that a=b/c can be rewritten as c=b/a:

`a=(b)/(c)\qquad\text{given}\\\\ac=b\qquad\text{multiply by $c$}\\\\c=(b)/(a)\qquad\text{divide by $a$, effectively swapping $a$ and $c$}`

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1. f - 7 = 9/a . . . . use the above shortcut

f = 9/a +7 . . . . add 7

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2. y -5 = 3x . . . . . subtract 5

x = (y -5)/3 . . . . divide by 3

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3. y +2 = 3/x . . . . add 2

x = 3/(y +2) . . . . use the above shortcut

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4. P +9 = 4l . . . . add 9

l = (P +9)/4 . . . divide by 4