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3/5x + 1/3 =42 solve for x

User Beefchimi
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1 Answer

3 votes

9514 1404 393

Answer:

x = 69 4/9

Explanation:

There are a couple of approaches you can take to this. The usual one would be to "clear fractions" by multiplying by 15.

15(3/5x) +15(1/3) = 15(42)

9x +5 = 630

Now, we can subtract 5 and divide by 9.

9x = 625 . . . . subtract 5 from both sides

x = 625/9 = 69 4/9

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Another way to solve this is to multiply by 5/3 to make the coefficient of x be 1.

(5/3)(3/5x) +(5/3)(1/3) = (5/3)(42)

x +5/9 = 70

Now, we can subtract 5/9 from both sides.

x = 69 4/9

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Working it in the usual "two-step equation" manner, you would subtract 1/3 first, then multiply by 5/3. IMO, this is messier, as you have ...

(5/3)(3/5x) = (5/3)(41 2/3)

x = (5/3)(125/3) = 625/9 = 69 4/9

User Leon Van Der Walt
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5.2k points