Answer: p=-12 *The answer should be negative sign.*
Explanation:
addition property of equality is adding the same number to both sides of an equation does not change the equation.
a+c=b+c
add numbers/similar elements
-10p+9p=-p
-p=12
divide by -1 both sides of an equation.
-p/-1=12/-1
simplify.
12/1=12
It's changes positive to negative sign.
p=-12
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