# Khan/khan-exercises

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143 lines (141 sloc) 6.888 kb
 One-step equations

Solve equations in the forms:

\qquad x + 5 = 10

\qquad 5 + x = 10

\qquad 10 = x + 5

\qquad 10 = 5 + x

randVar() randRangeNonZero(-30, 30) randRangeNonZero(-30, 30)

Solve for X:

X= B - A

A + X = B

Add abs(A) to both sides: Subtract abs(A) from both sides:

\qquad \begin{eqnarray} \\ A + X &=& B \\ \\ \red{A < 0 ? "+" : "-"abs(A)} && \red{A < 0 ? "+" : "-"abs(A)} \end{eqnarray}

\qquad \begin{eqnarray} \hphantom{A + X} &\hphantom{=}& \hphantom{B} \\ X &=& B \red{- A} \\ \end{eqnarray}

Simplify.

\qquad X = B - A

X + A = B

Add abs(A) to both sides: Subtract abs(A) from both sides:

\qquad \begin{eqnarray} \\ X + A &=& B \\ \\ \red{A < 0 ? "+" : "-"abs(A)} && \red{A < 0 ? "+" : "-"abs(A)} \end{eqnarray}

\qquad \begin{eqnarray} \hphantom{A + X} &\hphantom{=}& \hphantom{B} \\ X &=& B \red{- A} \\ \end{eqnarray}

Simplify.

\qquad X = B - A

B = A + X

Add abs(A) to both sides: Subtract abs(A) from both sides:

\qquad \begin{eqnarray} \\ \hphantom{B \red{- A}} &\hphantom{=}& \hphantom{X} \\ B &=& A + X \\ \\ \red{A < 0 ? "+" : "-"abs(A)} && \red{A < 0 ? "+" : "-"abs(A)} \\ \end{eqnarray}

\qquad \begin{eqnarray} \\ B \red{- A} &=& X \\ \end{eqnarray}

Simplify.

\qquad X = B - A

B = X + A

Add abs(A) to both sides: Subtract abs(A) from both sides:

\qquad \begin{eqnarray} \\ \hphantom{B \red{- A}} &\hphantom{=}& \hphantom{X} \\ B &=& X + A \\ \\ \red{A < 0 ? "+" : "-"abs(A)} && \red{A < 0 ? "+" : "-"abs(A)} \\ \end{eqnarray}

\qquad \begin{eqnarray} \\ B \red{- A} &=& X \\ \end{eqnarray}

Simplify.

\qquad X = B - A

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