Question

if x+y = 4 and 2x -5y=1 then find x by solving quations​

Answer 1

Given Equation :-

• x + y = 4⠀⠀.... [1]
• 2x - 5y = 1⠀.... [2]

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To find :-

• Value of x.

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Solution :-

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Multiplying [1] equation by 2, we get

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$\tt\longrightarrow{2x + 2y = 8}$⠀⠀... [3]

$\tt\longrightarrow{2x - 5y = 1}$⠀⠀... [4]

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Subtracting [4] from [3]

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$\tt\longmapsto{2x + 2y - (2x - 5y) = 8 - 1}$

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$\tt\longmapsto{\cancel{2x} + 2y - \cancel{2x} + 5y = 7}$

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$\tt\longmapsto{7y = 7}$

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$\tt\longmapsto{y = \dfrac{7}{7}}$

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$\tt\longmapsto{y = 1}$

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Substituting the value of y in [1]

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$\tt\longmapsto{x + 1 = 4}$

$\tt\longmapsto{x = 4 - 1}$

$\tt\longmapsto{x = 3}$

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Hence,

• Value of x is 3.

Answer 2

Answer:

x = 5/3

Step-by-step explanation:

x + y=4 eq.1

2x - 5y=1 eq.2

Multiply eq.1 by 2

(x + y = 4)*2

2x + 2y = 8 eq.3

subtract eq.2 from eq.3

(2x - 5y)-(2x + 2y)= 1 - 8

-3y = -7

y = -7/-3

y = 7/3

put the value of y in eq.1

x + 7/3 = 4

x = 4 - 7/3

x = 12-7 / 3

x = 5/3