Solve using substitution.

-7x + 9y = 20

y = 10

x=10

Step-by-step explanation:

1. substitute y for 10 getting - 7x + 9 (10) = 20

2. 9 (10) = 90

3. with - 7x+90=20 subtract 90 on both sides getting - 7x = - 70

4. then divide by - 7 on both sides getting x=10

5. to check u substitute x with 10 and y with 10 getting - 7 (10) + 9 (10) = 20. then multiply and add/subtract to get 20=20