Q. ( t = frac{(2 – x)(3 – x)}{3x^2 – 7x + 6} ).
Answer
First factor the numerator.
\((2-x)(3-x)=(-(x-2))(-(x-3))=(x-2)(x-3)\)
So, the expression becomes:
\(t=\frac{(x-2)(x-3)}{3x^2-7x+6}\)
Expand the numerator.
\((x-2)(x-3)=x^2-5x+6\)
Therefore:
\(t=\frac{x^2-5x+6}{3x^2-7x+6}\)
No factor cancels with the denominator.
Now check whether the denominator can equal zero for real \(x\). Use the discriminant.
\(D=b^2-4ac\)
For \(3x^2-7x+6\), we have \(a=3\), \(b=-7\), and \(c=6\).
\(D=(-7)^2-4(3)(6)=49-72=-23\)
Since \(-23<0\), the denominator has no real zeros.
So, the expression is defined for all real \(x\).
Final result: \(t=\frac{x^2-5x+6}{3x^2-7x+6}\)
Detailed Explanation
We are given the rational expression
\(t=\dfrac{(2-x)(3-x)}{3x^{2}-7x+6}\).
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Rewrite the numerator in a standard factor form.
Observe that each factor of the numerator can be written by factoring out a negative sign:
\(2-x = -(x-2)\) and \(3-x = -(x-3)\).
Multiplying these two equalities gives
\((2-x)(3-x) = \bigl(-(x-2)\bigr)\bigl(-(x-3)\bigr) = (+1)\,(x-2)(x-3) = (x-2)(x-3).\)
Thus the numerator simplifies to \((x-2)(x-3)\).
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Attempt to factor the denominator and check for common factors.
The denominator is the quadratic \(3x^{2}-7x+6\). To see whether it factors over the real numbers, compute its discriminant:
\(\Delta = b^{2}-4ac = (-7)^{2}-4\cdot 3\cdot 6 = 49-72 = -23.\)
Because \(\Delta = -23 < 0\), the quadratic has no real roots and therefore does not factor over the real numbers into linear real factors. In particular, it does not share any linear factor with the numerator \((x-2)\) or \((x-3)\).
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Write the simplified form and state the domain.
Using the numerator rewrite and the fact that no cancellation with the denominator is possible, the expression simplifies to
\(t = \dfrac{(x-2)(x-3)}{3x^{2}-7x+6}.\)
Because the denominator \(3x^{2}-7x+6\) has no real zeros (discriminant negative) and the leading coefficient 3 is positive, the denominator is never zero for any real x. Therefore the expression is defined for every real number x; the domain is all real numbers, \(\mathbb{R}\).
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Optional: expanded numerator form (equivalent expression).
Expanding the numerator gives \( (x-2)(x-3) = x^{2}-5x+6\), so an equivalent form is
\(t = \dfrac{x^{2}-5x+6}{3x^{2}-7x+6}.\)
No further simplification by cancellation is possible over the real numbers.
Final result: \(t = \dfrac{(x-2)(x-3)}{3x^{2}-7x+6}\), domain: all real numbers.
Algebra FAQs
What is the domain of \(t=\frac{(2-x)(3-x)}{3x^2-7x+6}\)?
Can this expression be simplified by canceling factors?
Where are the x-intercepts (zeros) of \(t\)?.
Are there any vertical or removable discontinuities?
What is the horizontal asymptote as \(x\to\pm\infty\)?
What is the y-intercept \(t(0)\)?
Where is \(t\) positive or negative?
How to solve for \(x\) given a value of \(t\) (invert)?
What are useful steps to sketch the graph quickly?
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