Question 697142
Hi, you are on the right track but the trick is that there are two equations.
Given:
Y = Age of Jane
X = Age of Mary Lou
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Setup:
Equation 1: {{{Y = X + 4}}}
Equation 2: {{{Y * X = 32}}}
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Since equation 1 is already solved for Y, plug (X + 4) into equation 2 for Y.
Equation 2: {{{Y * X = 32}}}
{{{(X + 4)*X = 32}}}
Simplify
{{{X^2 + 4X = 32}}}
Subtract 32 from both sides to set the equation equal to zero
{{{X^2 + 4X - 32 = 0}}}
You can now factor the equation or use the quadratic equation.
Here is the quadratic equation approach.
*[invoke quadratic "X", 1, 4, -32]
So X is 4 or -8.
Since age is a positive number this means that Mary Lou is 4
Now plug 4 into equation 1 for X to solve for Jane's age
Equation 1: {{{Y = X + 4}}}
{{{Y = (4) + 4}}}
{{{highlight(Y = 8)}}}