Solved on Jan 22, 2024

Estimate and solve for x in equations: a) 35=5(3x)35=5(3^{x}), b) 117=3×2x117=3\times2^{x}, c) 1000=500(1+0.08)x1000=500(1+0.08)^{x}, d) 45=100(1/2)x45=100(1/2)^{x}. Round answers to 3 decimal places.

STEP 1

Assumptions
1. We will solve each equation for xx.
2. We will use logarithms to solve the exponential equations.
3. We will round the final answers to three decimal places.

STEP 2

Start with equation (a) 35=5(3x)35=5\left(3^{x}\right).

STEP 3

Divide both sides of the equation by 5 to isolate the exponential term.
3x=3553^{x} = \frac{35}{5}

STEP 4

Calculate the right side of the equation.
3x=73^{x} = 7

STEP 5

Take the natural logarithm of both sides to solve for xx.
ln(3x)=ln(7)\ln(3^{x}) = \ln(7)

STEP 6

Use the logarithmic property ln(ab)=bln(a)\ln(a^{b}) = b \cdot \ln(a) to simplify the left side of the equation.
xln(3)=ln(7)x \cdot \ln(3) = \ln(7)

STEP 7

Divide both sides by ln(3)\ln(3) to solve for xx.
x=ln(7)ln(3)x = \frac{\ln(7)}{\ln(3)}

STEP 8

Calculate the value of xx using a calculator and round to three decimal places.
xln(7)ln(3)1.771x \approx \frac{\ln(7)}{\ln(3)} \approx 1.771

STEP 9

Now solve equation (c) 1000=500(1+0.08)x1000=500(1+0.08)^{x}.

STEP 10

Divide both sides of the equation by 500 to isolate the exponential term.
(1+0.08)x=1000500(1+0.08)^{x} = \frac{1000}{500}

STEP 11

Calculate the right side of the equation.
(1+0.08)x=2(1+0.08)^{x} = 2

STEP 12

Take the natural logarithm of both sides to solve for xx.
ln((1+0.08)x)=ln(2)\ln((1+0.08)^{x}) = \ln(2)

STEP 13

Use the logarithmic property ln(ab)=bln(a)\ln(a^{b}) = b \cdot \ln(a) to simplify the left side of the equation.
xln(1.08)=ln(2)x \cdot \ln(1.08) = \ln(2)

STEP 14

Divide both sides by ln(1.08)\ln(1.08) to solve for xx.
x=ln(2)ln(1.08)x = \frac{\ln(2)}{\ln(1.08)}

STEP 15

Calculate the value of xx using a calculator and round to three decimal places.
xln(2)ln(1.08)9.006x \approx \frac{\ln(2)}{\ln(1.08)} \approx 9.006

STEP 16

Now solve equation (b) 117=3×2x117=3 \times 2^{x}.

STEP 17

Divide both sides of the equation by 3 to isolate the exponential term.
2x=11732^{x} = \frac{117}{3}

STEP 18

Calculate the right side of the equation.
2x=392^{x} = 39

STEP 19

Take the natural logarithm of both sides to solve for xx.
ln(2x)=ln(39)\ln(2^{x}) = \ln(39)

STEP 20

Use the logarithmic property ln(ab)=bln(a)\ln(a^{b}) = b \cdot \ln(a) to simplify the left side of the equation.
xln(2)=ln(39)x \cdot \ln(2) = \ln(39)

STEP 21

Divide both sides by ln(2)\ln(2) to solve for xx.
x=ln(39)ln(2)x = \frac{\ln(39)}{\ln(2)}

STEP 22

Calculate the value of xx using a calculator and round to three decimal places.
xln(39)ln(2)5.285x \approx \frac{\ln(39)}{\ln(2)} \approx 5.285

STEP 23

Finally, solve equation (d) 45=100(12)x45=100\left(\frac{1}{2}\right)^{x}.

STEP 24

Divide both sides of the equation by 100 to isolate the exponential term.
(12)x=45100\left(\frac{1}{2}\right)^{x} = \frac{45}{100}

STEP 25

Calculate the right side of the equation.
(12)x=0.45\left(\frac{1}{2}\right)^{x} = 0.45

STEP 26

Take the natural logarithm of both sides to solve for xx.
ln((12)x)=ln(0.45)\ln\left(\left(\frac{1}{2}\right)^{x}\right) = \ln(0.45)

STEP 27

Use the logarithmic property ln(ab)=bln(a)\ln(a^{b}) = b \cdot \ln(a) to simplify the left side of the equation.
xln(12)=ln(0.45)x \cdot \ln\left(\frac{1}{2}\right) = \ln(0.45)

STEP 28

Divide both sides by ln(12)\ln\left(\frac{1}{2}\right) to solve for xx.
x=ln(0.45)ln(12)x = \frac{\ln(0.45)}{\ln\left(\frac{1}{2}\right)}

STEP 29

Calculate the value of xx using a calculator and round to three decimal places.
xln(0.45)ln(12)1.137x \approx \frac{\ln(0.45)}{\ln\left(\frac{1}{2}\right)} \approx 1.137
The solutions for each equation are:
a) x1.771x \approx 1.771 c) x9.006x \approx 9.006 b) x5.285x \approx 5.285 d) x1.137x \approx 1.137

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