Answer:
$775 = $550 + needs
or
needs = $775 - 550
Step-by-step explanation:
Most folks would figure the solution as the difference of the numbers without bothering to write an equation. As the second equation above indicates, you certainly can put that difference in equation form.
The first equation above is an expression of the fact that the needed amount is what is required to bring 550 up to 775. This is perhaps what you're expected to write.
The first equation shown is solved by subtracting 550 from both sides of the equation, resulting in the second equation shown.
