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Vadim26 [7]
2 years ago
5

If 2x + 5y=21 and x+y=3, then what is the value of x?

Mathematics
1 answer:
katrin2010 [14]2 years ago
8 0
The answer is D I think
Given the 2 equations
2x + 5y = 21 → (1)
x + y = 3 → (2)
Rearrange (2) expressing y in terms of x, by subtracting x from both sides
y = 3 - x ← Substitute into (1)
2x + 5(3 - x) = 21 ← distribute and simplify left side
2x + 15 - 5x = 21
- 3x + 15 = 21 ( subtract 15 from both sides )
- 3x = 6 ( divide both sides by - 3 x = - 2 → D
X=-2
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<u>Answer:</u>

x = 4 (extraneous solution)

<u>Step-by-step explanation:</u>

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This solution is extraneous. Reason being that even if it can be solved algebraically, it is still not a valid solution because if we substitute back x=4, we will get two fractions with zero denominator which would be undefined.

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2 years ago
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3 0
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Yes! Let me help you!

Here is the original equation, lets solve this step-by-step

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Now, lets find out how. 

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3 0
3 years ago
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