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Rewrite the equation using exponent rules.

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6. Solve for xx in 22x−18×2x=402^{2x} - 18 \times 2^x = 40

  1. Rewrite the equation using exponent rules.

    We know that 22x=(2x)22^{2x} = (2^x)^2.
    So the equation becomes:

    (2x)2−18×2x=40(2^x)^2 - 18 \times 2^x = 40
  2. Introduce a substitution to form a quadratic equation.

    Let y=2xy = 2^x. Substitute yy into the equation:

    y2−18y=40y^2 - 18y = 40
  3. Rearrange the equation into standard quadratic form and solve for yy.

    y2−18y−40=0y^2 - 18y - 40 = 0

    Factor the quadratic equation:

    (y−20)(y+2)=0(y - 20)(y + 2) = 0

    This gives two possible values for yy:

    y−20=0  ⟹  y=20y - 20 = 0 \implies y = 20 y+2=0  ⟹  y=−2y + 2 = 0 \implies y = -2
  4. Substitute back 2x2^x for yy and solve for xx.

    Case 1: y=20y = 20

    2x=202^x = 20

    Take the logarithm of both sides (e.g., base 10 or natural log):

    log⁡(2x)=log⁡(20)\log(2^x) = \log(20) xlog⁡(2)=log⁡(20)x \log(2) = \log(20) x=log⁡(20)log⁡(2)x = \frac{\log(20)}{\log(2)}

    Using a calculator:

    x≈1.301030.30103≈4.3219x \approx \frac{1.30103}{0.30103} \approx 4.3219

    Case 2: y=−2y = -2

    2x=−22^x = -2

    An exponential function with a positive base, like 2x2^x, is always positive for real values of xx. Therefore, there is no real solution for xx in this case.

    The only real solution for xx is:

    x=log⁡(20)log⁡(2)≈4.3219\boxed{x = \frac{\log(20)}{\log(2)} \approx 4.3219}

    7. Given that Sin(x−30)0−Cos(4x)0=0\text{Sin}(x - 30)^0 - \text{Cos}(4x)^0 = 0. Find the tan(2x+30)0\text{tan}(2x+30)^0

  5. Rearrange the given equation.

    Sin(x−30)0=Cos(4x)0\text{Sin}(x - 30)^0 = \text{Cos}(4x)^0
  6. Use the trigonometric identity Sin(θ)=Cos(900−θ)\text{Sin}(\theta) = \text{Cos}(90^0 - \theta).

    This means that the angles must be complementary (or differ by multiples of 3600360^0, but for basic problems, we assume the simplest case).
    So, we can equate the angles:

    (x−30)0+(4x)0=900(x - 30)^0 + (4x)^0 = 90^0
  7. Solve for xx.

    x−30+4x=90x - 30 + 4x = 90 5x−30=905x - 30 = 90 5x=90+305x = 90 + 30 5x=1205x = 120 x=1205x = \frac{120}{5} x=24x = 24
  8. Substitute the value of xx into the expression tan(2x+30)0\text{tan}(2x+30)^0.

    First, calculate the angle:

    2x+30=2(24)+302x + 30 = 2(24) + 30 2x+30=48+302x + 30 = 48 + 30 2x+30=782x + 30 = 78

    Now, find the tangent of this angle:

    tan(78)0\text{tan}(78)^0

    Using a calculator:

    tan(78)0≈4.7046\text{tan}(78)^0 \approx 4.7046

    The value is:

    tan(2x+30)0≈4.7046\boxed{\text{tan}(2x+30)^0 \approx 4.7046}
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