Question

Which of these strategies would eliminate a variable in the system of equations?

8.3 + 5y = -7
- 7x + y = -4

Answer 1

Multiplying the first equation by 1 and the second equation by 5 to eliminate the y variable .

x= 0.3

y= -1.9

Explanation:

8.3x + 5y = -7 ----------i

- 7x + y = -4 -----------ii

Multiply the first equation by 1 and the second equation by 5 to eliminate the y variable as below;

[8.3x + 5y = -7 ]1

[- 7x + y = -4]5

8.3x + 5y = -7

-35 x + 5y = -20

perform subtraction to eliminate y as

8.3x --35x = -7--20

43.3 x = 13

x= 13/43.3

x= 0.3

Using equation ii ;

-7x + y = -4

-7 * 13/43.3 + y = -4

-91/43.3 + y = -4

y= -4 + 91/43.3

y= -4 + 2.1

y= -1.9