Question

Evaluate Dx -4x+7y=1 25=2x+5y

Answer 1

Equation 1)  -4x + 7y = 1
Equation 2)  25 = 2x + 5y

For both equations, move the variables all onto one side, preferably the left side.

To do so, for equation 2, subtract 2x from both sides, as well as subtracting 5y from both sides, and then subtracting 25 from both sides.

2) -2x - 5y = -25
1) -4x + 7y = 1

Multiply all of equation 2 by 2.

2)  2(-2x - 5y = -25)

2)  -4x - 10y = -50
1)  -4x + 7y = 1

Subtract the equations from each other.

-17y = -51

Divide both sides by -17.

y = 51/17

y = 3

Plug in 3 for y in the first equation.

-4x + 7y = 1

-4x + 7(3) = 1

-4x + 21 = 1

-4x = 1 - 21

-4x = -25

x = -25/-4

x = 25/4

x = 6 1/4

(6 1/4, 3) 

~Hope I helped!~