Question

11

Select the correct answer.
The elimination method is ideal for solving this system of equations. By which number must you multiply the second equation to eliminate the
yavariable, and what is the solution for this system?
x + 3y - 42
2x-y-14
OA. Multiply the second equation by-3. The solution is x = 12. y - 9.
ов.
Multiply the second equation by-2. The solution is x-12. y = 10.
OC.
Multiply the second equation by 2. The solution is x - 15, y = 9.
OD
Multiply the second equation by 3. The solution is x - 12. = 10.
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Answer 1

D. Multiply the second equation by 3. The solution is x = 12, y = 10

Explanation:

Given:

x + 3y = 42 (first equation)

2x - y = 14 (second equation)

To solve by elimination, starting with elimination of the y-variable, multiply the second equation by 3 to get a third equation.

2x - y = 14 (2nd eqn.) × 3

6x - 3y = 42 (3rd equation)

Add the 3rd equation and the 1st equation together.

x + 3y = 42 (first equation)

6x - 3y = 42 (3rd equation)

7x = 84

7x/7 = 84/7

x = 12

To find y, substitute x = 12 in the first equation

x + 3y = 42 (first equation)

12 + 3y = 42

12 + 3y - 12 = 42 - 12

3y = 30

3y/3 = 30/3

y = 10

Solution is x = 12, y = 10