Question

If 3x – 9y = 21 and 6x + 3y = 21, which of these could be a value of x or y? Select all that apply.
–5
–1
5
4
–2
9

Answer 1

Answer:

x=4

y= -1

Step-by-step explanation:

3x-9y=21 × 2

= 6x - 18y = 42

6x+3y=21

6x-18y= 42

21y= -21

y= -1

6x+ 3y= 21

6x= 21-3y= 21+3

x= 4