Question

Solve each system of linear equations by substitution [5x + y =8
[2x +y=5

Answer 1

x= 1 and y= 3

Explanation:

5x + y =8 ......... equation 1

2x +y=5 .......... equation 2

make y the subject of the formula in equation 1

y = 8 - 5x .......... equation 3

Substitute y= 8- 5x in equation 2

2x + (8 - 5x) = 5

2x + 8 - 5x= 5

Collect like terms

2x -5x =5 - 8

-3x = -3

divide both sides by coefficient of x

-3x/-3 = -3/-3

x = 1

Substitute x= 1 in equation 3

y = 8- 5(1)

y = 8 - 5

y= 3

Answer 2

x=1, y=3. (1, 3).

Explanation:

5x+y=8

2x+y=5

---------------

-(5x+y)=-8

2x+y=5

----------------

-5x-y=-8

2x+y=5

------------

-3x=-3

3x=3

x=3/3=1

2(1)+y=5

2+y=5

y=5-2

y=3