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let's evaluate this expression
[tex]\pmb{\displaystyle\frac{8-m}{n+p^2} }[/tex]
[tex]\pmb{\displaystyle\frac{8-8}{2+7^2}}[/tex] (step 1)
[tex]\pmb{\displaystyle\frac{0}{2+49}}[/tex] (step 2)
simplify:
[tex]\pmb{\displaystyle\frac{0}{51}}[/tex] (step 3)
[tex]\pmb{0}[/tex] (step 4)
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Hope everything is clear; if you need any more clarification/explanation, kindly let me know, and I will comment and/or edit my answer :)