Question

Given that
R
=
3
x
+
9
y

Find
y
when
x
=
7
and
R
=
21

Answer 1

Answer:

y = 0

Step-by-step explanation:

r = 3x + 9y

x = 7

r = 21

21 = 3(7) + 9y

21 = 21 + 9y

21 - 21 = 9y

9y = 0

y = 0

Answer 2

Step-by-step explanation:

R=3x+9y

21=3(7)+9y

21=21+9y

9y=0

y=0

Thank you