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.

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.

answer: i guess 5 units?

step-by-step explanation:

x =-.20752

step-by-step explanation:

4^(x+2)=12

4^(x+2)=12

take the log base 4 on each side

log 4 (4^(x+2) = log 4(12)

we know log b(a^y) = y log b (a)

(x+2) log 4(4) = log 4 (12)

x+2 = log 4 (12)

we know   logb c = loga c/loga b

we want to convert to base 10   so a = 10

by default, we do not write the 10   c = 4   and b = 10

log4 10 = log 12/log 4

log4 10 = log 12/ log 4

x+2 = log 12/ log 4

subtract 2 from each side

x +2 -2 = log 12/ log 4 -2

x = 1.79248125 -2

x =-.20752