Question

For what value of the constant c does the system

3x + 4y = 7,
6x + 4y = c - 4y.

Answer 1

Step 1: get “c” by itself by adding 4y on each side

6x + 4y + 4y = c - 4y + 4y

6x + 8y = c

Step 2: convert the first expression to 6x + 8y by multiplying by 2 on both sides

2 ( 3x + 4y) = 2 (7)

6x + 4y = 14

Step 3: bc we know that 6x + 4y = 14, we can substitute it in to our first step expression

6x + 4y = c

14 = c

Step 4: answer

c = 14

Answer 2

Answer: -14

Explanation