Solve the system of equations: 3x-5y = 23 and 4x-5y = -7

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hala718's profile pic

hala718 | High School Teacher | (Level 1) Educator Emeritus

Posted on

3x-5y = 23................(1)

4x -5y = -7 .................(2)

We will use the elimination method to solve.

We will subtract (1) from (2).

==> x = -30

Now we will substitute into (2) to find y.

==> 4x -5y = -7

==> 4*-30 - 5y = -7

==> -120 - 5y = -7

==>5y = -120 + 7 = -113

==> y= -113/5

Then the answer is the pair ( -30, -113/5)

tonys538's profile pic

tonys538 | Student, Undergraduate | (Level 1) Valedictorian

Posted on

The system of equations 3x-5y = 23 and 4x-5y = -7 has to be solved.

3x-5y = 23

3x = 23 + 5y

x = (23 + 5y)/3

Substitute this in the equation 4x-5y = -7

4*(23 + 5y)/3 - 5y = -7

4*(23 + 5y) - 5y = -21

92 + 20y - 15y = -21

5y = -113

y = -113/5

x = (23 + 5*(-113/5))/3

= (23 - 113)/3

= -30

The solution of the system of equations is x = -30 and y = -113/5

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