Answer:

Step-by-step explanation:
<h3>to understand this</h3><h3>you need to know:</h3>
- linear equation
- linear equation word problems
- PEMDAS
<h3>tips and formulas:</h3>
<h3>let's solve:</h3>
all we need to care about the middle condition which is
<h3>the new test score is 15 points more than the original score</h3>
given that
original score is x
New score is y
if you pay attention to the given condition
we can find it same as linear equation
therefore
according to the question
the equation is
<h2>y=x+15</h2>