Solve this System: 4x - 8y = 16 and -x - 2y = 24

Question

4x8y=16 4x-8y=16

x2y=24 -x-2y=24

Video Solution

Step-by-Step Solution

To solve this system using the elimination method, we'll follow these steps:

  • Step 1: Multiply the second equation by 4 to align the x x -coefficients:

The second equation is x2y=24 -x - 2y = 24 . Multiply it by 4:

4x8y=96-4x - 8y = 96

  • Step 2: Add this to the first equation:

The first equation is 4x8y=16 4x - 8y = 16 .

Adding the scaled second equation gives:

(4x8y)+(4x8y)=16+96(4x - 8y) + (-4x - 8y) = 16 + 96

Solving gives:

16y=112-16y = 112

  • Step 3: Solve for y y :

Divide both sides by 16-16:

y=11216=7y = \frac{112}{-16} = -7

  • Step 4: Substitute y=7 y = -7 into the original second equation:

Use x2y=24 -x - 2y = 24:

x2(7)=24-x - 2(-7) = 24

x+14=24-x + 14 = 24

Subtract 14 from both sides:

x=10-x = 10

Multiply by 1-1:

x=10x = -10

Thus, the solution to the system is x=10 x = -10 and y=7 y = -7 .

Therefore, the solution to the problem is (x,y)=(10,7)(x, y) = (-10, -7).

Answer

x=10,y=7 x=-10,y=-7