Question Details

Find the value of x and y for the given system of equations : 3x+4y=6, 5x-4y=4

Options

A

x=-(5/4), y=-(16/9)

B

x=5/4, y=-(9/16)

C

x=-(5/4), y=16/9

D

x=5/4, y=9/16

Correct Answer :

x=5/4, y=9/16

Solution :

The correct option is x=5/4, y=9/16.

To find the values of x and y, we can solve the given system of linear equations step-by-step using the elimination method. The given equations are:

1) 3x+4y=6

2) 5x4y=4

Step 1: Eliminate the variable y by adding the two equations.
Notice that the coefficient of y in the first equation is +4 and in the second equation is 4. Since these coefficients are opposites, we can add Equation (1) and Equation (2) directly to eliminate y:

(3x+4y)+(5x4y)=6+4

Combining the like terms gives:

8x=10

Step 2: Solve for x.
Divide both sides of the equation by 8:

x=108

Simplifying the fraction by dividing the numerator and the denominator by their greatest common divisor, 2, we get:

x=54

Step 3: Substitute the value of x back into one of the original equations to solve for y.
Let us substitute x=54 into Equation (1):

354+4y=6

154+4y=6

Subtract 154 from both sides of the equation:

4y=6154

To perform the subtraction, find a common denominator for the right side:

4y=244154

4y=94

Now, divide both sides by 4 to find y:

y=94×4

y=916

Thus, the solution to the system of equations is x=54 and y=916.

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