Question

if a+b=5 and 3a+2b=20, then what is 3a+b equal to?

Answer 1

$\boxed{\boxed{3a + b = 25}}\\\\a+b = 5\\3a + 2b = 20\\\\b = 5 - a\\\\3a + 2b = 20\\3a + 2(5-a) = 20\\3a + 10 - 2a = 20\\3a - 2a = 20 - 10\\a = 10\\\\a + b = 5\\10 + b = 5\\b = 5 - 10\\ b = -5\\\\3a + b = 3 \cdot 10 + (-5) = 30 - 5 = 25$