Question

-3a+5b=35. A+2b=3

Show me how to do this

Answer 1

Treat "A" as the same variable a. Use substitution.

1) a + 2b = 3 => a = 3 − 2b
2) Substitute into -3a + 5b = 35:
-3(3 − 2b) + 5b = 35
-9 + 6b + 5b = 35
11b − 9 = 35
11b = 44
b = 4

3) Now find a: a = 3 − 2b = 3 − 2(4) = 3 − 8 = −5.

Check: −3(−5) + 5(4) = 15 + 20 = 35.
Solution: a = −5, b = 4.