Question
Beginning algebra students sometimes make the following error when squaring a binomial:$$(x+5)^{2}=x^{2}+25$$(a) Substitute a value for $x$ to verify that this is an error.(b) What is the correct expansion for $(x+5)^{2} ?$
Step 1
\begin{align*} (x+5)^{2}&=x^{2}+25\\ (1+5)^{2}&=1^{2}+25\\ 36&=26 \end{align*} Since $36 \neq 26$, the expression is incorrect. Show more…
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An Algebra Error Beginning algebra students sometimes make the following error when squaring a binomial: $$ (x+5)^{2}=x^{2}+25 $$ (a) Substitute a value for $x$ to verify that this is an error. (b) What is the correct expansion for $(x+5)^{2} ?$
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