Respuesta :

Answer: p=-12 *The answer should be negative sign.*

Step-by-step 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

Hope this helps!

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