Question

The equations –a – 7b = 14 and –4a – 14b = 28 represent a system of linear equations. Which statement correctly explains how to eliminate the variable b when solving the system of equations? A. Multiply the first equation by –2 and add it to the second equation. Then solve the resulting equation, –2a = 0. B. Multiply the first equation by 2 and add it to the second equation. Then solve the resulting equation, –2a = 0. C. Divide the second equation by –4 and add it to the first equation. D. Divide the second equation by 4 and add it to the first equation.

Answer 1

Answer:

A. Multiply the first equation by –2 and add it to the second equation. Then solve the resulting equation, –2a = 0.

Step-by-step explanation:

Answer 2

Answer:

A. Multiply the first equation by –2 and add it to the second equation. Then solve the resulting equation, –2a = 0.

Step-by-step explanation:

–a – 7b = 14

–4a – 14b = 28

B. Multiply the first equation by 2 and add it to the second equation. Then solve the resulting equation, –2a = 0.

This option is wrong because on adding the two equations, the coefficient of b will be -28. No elimination was carried out.

C. Divide the second equation by –4 and add it to the first equation.

In the second equation, if we divide the coefficient of b, -14 by -4, our result will be 7/2. We cannot eliminate b using this method.

D. Divide the second equation by 4 and add it to the first equation.

In the second equation, if we divide the coefficient of b, -14 by 4, our result will be -7/2. We cannot eliminate b using this method.