Question

Solve the system of linear equations by substitution. 5x+2y=9 y-x= 8

Answer 1

x=1

y=9

Explanation:

5x+2y=9 , y-x= 8

y=8+x

put 8+ x anywhere we see y

5x+2(8+x)=9

5x+16+2x=9

5x+2x+16=9

7x+16=9

16-9=7x

7=7x

divide both sides by 7

x=1

if x=1, then y-1=8

y=8+1

y=9

Answer 2

1. From equation 2(y-x=8)
2. y=8+x.....name equation 3
3. Sub equation 3 in equation 1
4. 5x+2(8+x)-9=0 (Transpose the 9)
5. 5x+16+2x-9=0 (Group the like terms)
6. 5x+2x+16-9
7. 7x+7
8. x=7+7=14
9. x=14