Answer: C. (3,21) - x= 3 ; y= 21
Step-by-step explanation:
y= 10x - 9 .(-1)
y = x + 18
-y= -10x + 9
y = x + 18
-9x + 27
x= 27
-9
x= 3
y = x + 18
y= 3 + 18
y= 21
Answer:
C. (3,21)
Step-by-step explanation:
multiply the 2nd equation by -10 to cancel out the x.
y = 10x - 9
-10(y = x + 18)
y = 10x - 9
-10y = -10x - 180
-9y = -189
y = 21
Now plug y = 21 into either original equation.
y = x + 18
21 = x + 18
Take 18 from each side.
3 = x
Answer: (3, 21)
