The problem has two parts. Part (a) requires us to solve the equation $(\frac{2}{3})^{x+2} = (\frac{3}{2})^{2-3x}$ for $x$. Part (b) gives us a diagram with $|PQ| = 4$ cm, $|QR| = 2$ cm, $|QT| = 2$ cm, and $|PT| = |TS| = 5$ cm, and asks us to find $|RS|$.

AlgebraExponentsEquationsGeometrySimilar Triangles
2025/6/3

1. Problem Description

The problem has two parts. Part (a) requires us to solve the equation (23)x+2=(32)23x(\frac{2}{3})^{x+2} = (\frac{3}{2})^{2-3x} for xx. Part (b) gives us a diagram with PQ=4|PQ| = 4 cm, QR=2|QR| = 2 cm, QT=2|QT| = 2 cm, and PT=TS=5|PT| = |TS| = 5 cm, and asks us to find RS|RS|.

2. Solution Steps

(a) To solve the equation (23)x+2=(32)23x(\frac{2}{3})^{x+2} = (\frac{3}{2})^{2-3x}, we can rewrite the right side of the equation using the property that (ab)1=ba(\frac{a}{b})^{-1} = \frac{b}{a}.
(32)23x=(23)(23x)=(23)2+3x(\frac{3}{2})^{2-3x} = (\frac{2}{3})^{-(2-3x)} = (\frac{2}{3})^{-2+3x}.
Now we have (23)x+2=(23)2+3x(\frac{2}{3})^{x+2} = (\frac{2}{3})^{-2+3x}.
Since the bases are equal, we can set the exponents equal to each other:
x+2=2+3xx+2 = -2+3x.
Subtract xx from both sides: 2=2+2x2 = -2 + 2x.
Add 2 to both sides: 4=2x4 = 2x.
Divide by 2: x=2x = 2.
(b) Since PQ=4|PQ|=4 and QR=2|QR|=2, the ratio PQQR=42=2\frac{|PQ|}{|QR|} = \frac{4}{2} = 2. Since PT=5|PT|=5 and QT=2|QT|=2, the ratio PTQT=52=2.5\frac{|PT|}{|QT|} = \frac{5}{2} = 2.5. The sides are not proportional.
We can say triangles PQTPQT and QRSQRS are similar if and only if PQQR=QTRS=PTQS\frac{PQ}{QR} = \frac{QT}{RS} = \frac{PT}{QS} and PQT=QRS\angle PQT = \angle QRS, QTP=RSS\angle QTP = \angle RSS and TPQ=SQR\angle TPQ = \angle SQR.
The length of RS can be found by observing that triangle PQT and triangle QRS may be similar.
The given information is PQ=4|PQ| = 4, QR=2|QR| = 2, QT=2|QT| = 2, PT=5|PT| = 5, TS=5|TS| = 5. We need to find RS|RS|.
Since QT is perpendicular to PS, triangles PQT and QTS are right triangles.
However, triangles PQT and QRS are not similar in general.
Let's consider the two right triangles PQT and a hypothetical right triangle similar to PQT with hypotenuse QR of length

2. In triangle PQT, we have $|PQ|=4$, $|QT|=2$, $|PT|=5$.

If triangle QRS is similar to triangle PQT, then QRPQ=RSPT=QSQT\frac{QR}{PQ} = \frac{RS}{PT} = \frac{QS}{QT} and 24=12\frac{2}{4} = \frac{1}{2}.
QRPQ=QT?\frac{|QR|}{|PQ|} = \frac{|QT|}{|?|} means 24=2?\frac{2}{4} = \frac{2}{|?|}. So ?=4|?| = 4.
QRPQ=RSPT\frac{|QR|}{|PQ|} = \frac{|RS|}{|PT|} means 24=RS5\frac{2}{4} = \frac{|RS|}{5}. So RS=245=52=2.5|RS| = \frac{2}{4} * 5 = \frac{5}{2} = 2.5.
We are not given that QRS is a right triangle. So the right triangle properties can not be used here.
PTQ=90\angle PTQ = 90. So QTPSQT \perp PS. In order to have triangle PQT similar to triangle QRS, we must have QTS\angle QTS a right angle and also QR/PQ=RS/PT|QR|/|PQ|=|RS|/|PT|, which gives us
RS=(QR/PQ)PT=(2/4)5=2.5|RS|=(|QR|/|PQ|)*|PT|=(2/4)*5=2.5.
Final Answer:

3. Final Answer

(a) x=2x=2
(b) RS=2.5|RS| = 2.5 cm