Question

subtract by horizontal method 7pqr-8p+3 from 10-4pqr+3p

Answer 1

  10-4pqr+3p

(-) 3+7pqr-8p   (you need to rearrange the values so that they                           can be added)

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  7-11pqr+11p is the answer

because it is subraction you need to make the expression  on the bottom negative in this case it was(3+7pqr-8p) which became (-3-7pqr+8p)