-x-y=1
-y=1+x
y=-1-x
-1-x=-2x+9
-x=-2x+10
x=10
y=-1-10
y=-11
X=15 its simple since there's base angles and straight angle
25%
since there are 4 books, and only one is a mathematics book, there is a 1/4 chance. in other words, 25%
The Answer To This Problem is: C.-4
Answer:4 in each package
Step-by-step explanation: