Respuesta :
Answer:
y=0
Step-by-step explanation:
R=3x+9y
(given)
21=3(7)+9y
21=21+9y
9y=21-21
9y=0
y=0
Answer:
y = 0
Step-by-step explanation:
Given
R = 3x + 9y , then
21 = 3(7) + 9y
21 = 21 + 9y ( subtract 21 from both sides )
0 = 9y ( divide both sides by 9 )
y = 0
