Question

Find the simultaneous solution of the following pairs of equations using an algebraic method: x=1+2y 2x+y=17. Please also give an explanation why.

Answer 1

The solution is x = 7 and y= 3

Solution:

Given pairs of equation are:

x = 1 + 2y ------- eqn 1

2x + y = 17 ------- eqn 2

We have to use algebraic method

Algebraic method involves substitution and elimination method

Let us use the substitution method

From equation 1, we can see that x is equal to 1 + 2y. If we substitute this for y in equation 2, we have:

2(1 + 2y) + y = 17

Solve for brackets

2 + 4y + y = 17

Combine the like terms which has same variable

2 + 5y = 17

5y = 17 - 2

5y = 15

Divide both sides of equation by 5

y = 3

So the value of y is 3. This value of y can be substituted into either equation 1 or 2 to find the value of x

Substitute y = 3 in eqn 1

x = 1 + 2(3)

x = 1 + 6

x = 7

So the solution is x = 7 and y = 3