Question

simultaneous equations 5x+y=28 x+y=2

Answer 1

Answer:

$( \frac{13}{2} \:, - \frac{9}{2} )$

Step-by-step explanation:

$5x + y = 28$

$x + y = 8$

Solve the equation for y by moving 'x' to R.H.S and changing its sign

$5x + y = 28$

$y = 2 - x$

Substitute the given value of y into the equation 5x + y = 28

$5x + 2 - x = 28$

Solve the equation for x

Collect like terms

$4x + 2 = 28$

Move constant to R.H.S and change its sign

$4x = 28 - 2$

Subtract the numbers

$4x = 26$

Divide both sides of the equation by 4

$\frac{4x}{4} = \frac{26}{4}$

Calculate

$x = \frac{26}{4}$

Reduce the numbers with 2

$x = \frac{13}{2}$

Now, substitute the given value of x into the equation y = 2 - x

$y = 2 - \frac{13}{2}$

Solve the equation for y

$y = - \frac{9}{2}$

The possible solution of the system is the ordered pair ( x , y )

$(x \: y) = ( \frac{13}{2} , \: - \frac{9}{2} )$

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Let's check if the given ordered pair is the solution of the system of equation:

plug the value of x and y in both equation

$5 \times \frac{13}{2} - \frac{9}{2} = 28$

$\frac{13}{2} - \frac{9}{2} = 2$

Simplify the equalities

$28 = 28$

$2 = 2$

Since , all of the equalities are true, the ordered pair is the solution of the system.

$(x \:, y \: ) = ( \frac{13}{2} \: , - \frac{9}{2})$

Hope this helps....

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Answer 2

Answer:

$\boxed{x=6.5} \\ \boxed{y=-4.5}$

Step-by-step explanation:

5x + y = 28

x + y = 2

Subtract both equations. (eliminating y variable)

4x + 0 = 26

4x = 26

Divide both sides by 4.

x = $\frac{26}{4}$

x = 6.5

Plug x as 6.5 in the second equation and solve for y.

6.5 + y = 2

Subtract 6.5 on both sides.

6.5 - 6.5 + y = 2 - 6.5

y = -4.5