Question

A system of equations is shown below:

Equation A: 2c = d − 8
Equation B: c = 3d + 8

Which of the following steps should be performed to eliminate variable d first?

Multiply equation B by 2.
Multiply equation A by 2.
Multiply equation B by 3.
Multiply equation A by −3.

Answer 1

@jim_thompson5910

Answer 2

what is the coefficient of the d term in equation 2?

Answer 3

in other words, what is the number in front of the d term in equation 2?

Answer 4

2

Answer 5

look again

Answer 6

2c

Answer 7

c = 3d + 8

what is the number in front of the d term

Answer 8

3

Answer 9

2c = d - 8 is the same as 2c = 1d - 8

what is the number in front of the d term

Answer 10

1

Answer 11

we have 1d in equation 1
we have 3d in equation 2

we want the d terms to add to 0, do they?

Answer 12

in other words, is 1d + 3d equal to 0d = 0 ?

Answer 13

Wouldn't it be quicker to directly substitute c into equation A?

Answer 14

@thomas5267 I got into a brawl with that question.

Answer 15

@thomas5267 yes but the directions specifically and simply ask what should you do to eliminate d first ? not even asking to solve

Answer 16

Yes that's just a personal rant lol.

Answer 17

multiply equation A by -3

Answer 18

thank you @triciaal for ending this two month old question. multiply equation A by -3 to get rid of the d is the right way to do this.