Question

2) 2x-3y=-1
y = x - 1

Answer 1

x = 4 and y = 3

Explanation:

You are looking for the value of x and y when: 2x - 3y = -1 and y = x - 1

Because you are given y in terms of x (the second equation given), substitute that into the first equation for y:

2x - 3y = -1 when y = x - 1

2x - 3(x - 1) = -1

expand left side:

2x - 3x + 3 = -1

combine x terms on left side:

-x + 3 = -1

subtract 3 from both sides:

-x + 3 - 3 = -1 - 3

-x = -4

divide both sides by -1:

-x/-1 = -4/-1

x = 4

now use x = 4 in one of the original equations to solve for y. For simplicity sake, we will use the second equation but the answer can also be found by substituting x = 4 into the first equation.

y = x - 1 when x = 4

y = 4 - 1

y = 3

Answer 2

x = 4; y = 3

Explanation:

2x - 3y = -1

y = x - 1

Copy the first equation.

Subtract x from both sides of the second equation and multiply both sides by 3. Write it below the first equation. Then add the equations eliminating y. Solve for x.

2x - 3y = -1

+ -3x + 3y = -3

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

-x = -4

x = 4

Now substitute 4 for x in the second original equation and solve for y.

y = x - 1

y = 4 - 1

y = 3

Answer: x = 4; y = 3