Answer:
$120, 400 + x = 620
Explanation:
A guitarist charges $400. He makes $620 for the whole night. He makes x amount of tips. To solve, write the equation 400 + x = 620.
Solve by subtracting 400 from both sides.
400 + x = 620
400 - 400 + x = 620 - 400
x = 120