Question

if 10x+y = 12 and x + 10y = 21, then what is the value of x+y ?​

Answer 1

Answer:

3

Step-by-step explanation:

10x+y=12. ---->1

x+10y=21. ----->2

multiply eq.1 with 10 on both sides

100x+10y=120 --->3

x+10y=21. ----->4

subtract 3-4

99x=99

x = 99/99

x = 1

substituting in eq1

10(1)+y = 12

y = 12-10

y = 2

x+y = 1+2 = 3