Question

Show and explain how replacing one equation by the

Answer 1

Answer:

x = 1/2 and y = 5

Step-by-step explanation:

First, let's multiply the first equation by two on the both sides:

$8x + 7y = 39 \times 2$

⇒ $16x + 14y = 78$

Now, the system is:

$16x + 14y = 78\\\\4x -14y = -68$

After adding this up in the column:

$(16x + 4x) + (14y - 14y) = 78 - 68\\\\20x = 10\\\\ x = 10/20 = 1/2$

y can be calculated by replacin the x:

$8x + 7y = 39\\\\ 8* 1/2 + 7y = 39\\\\4 + 7y = 39\\\\7y = 39 - 4\\\\7y = 35\\\\ y = \frac{35}{7} = 5$

x = 1/2 and y = 5

Answer 2

Answer: Using the linear combination method, you can multiply the first equation by 2 and add the equations to get 20x = 10. Dividing both sides by 20, x = 1/2. To solve for y, substitute 1/2 for x in the equation 8x + 7y = 39 to get 4 + 7y = 39. Solving this equation, y = 5. Checking this in the other equation, 4(1/2) – 14(5) = –68 results in 2 – 70 = –68 or –68 = –68. The solution of the system shown is (1/2, 5). The system 8x + 7y = 39 and 20x = 10 is formed by replacing 4x –14y = –68 by a sum of it and a multiple of 8x + 7y = 39. Since 20(1/2) = 10, the system 8x + 7y = 39 and 20x = 10 also has a solution of (1/2, 5).

Step-by-step explanation: this is the sample response

hope this helps you :3