QUESTION IMAGE
Question
algebra 2
unit 5 part 2 bonus
name
solve each equation. remember to check for extraneous solutions.
date
- $14 = 5 + \sqrt{11b - 7}$
- $\sqrt{4 - 3n} = n$
solve each equation.
- $(x - 25)^{\frac{3}{2}} - 2 = 727$
- $3 + 2(3v - 15)^{\frac{3}{2}} = 57$
Problem 1: \( 14 = 5 + \sqrt{11b - 7} \)
Step 1: Isolate the square root
Subtract 5 from both sides:
\( 14 - 5 = \sqrt{11b - 7} \)
\( 9 = \sqrt{11b - 7} \)
Step 2: Eliminate the square root
Square both sides:
\( 9^2 = (\sqrt{11b - 7})^2 \)
\( 81 = 11b - 7 \)
Step 3: Solve for \( b \)
Add 7 to both sides:
\( 81 + 7 = 11b \)
\( 88 = 11b \)
Divide by 11:
\( b = \frac{88}{11} = 8 \)
Step 4: Check for extraneous solutions
Substitute \( b = 8 \) into the original equation:
Left side: \( 14 \)
Right side: \( 5 + \sqrt{11(8) - 7} = 5 + \sqrt{88 - 7} = 5 + \sqrt{81} = 5 + 9 = 14 \)
Solution is valid.
Step 1: Eliminate the square root
Square both sides:
\( (\sqrt{4 - 3n})^2 = n^2 \)
\( 4 - 3n = n^2 \)
Step 2: Rearrange into quadratic form
\( n^2 + 3n - 4 = 0 \)
Step 3: Solve the quadratic equation
Factor:
\( (n + 4)(n - 1) = 0 \)
Solutions: \( n = -4 \) or \( n = 1 \)
Step 4: Check for extraneous solutions
- For \( n = -4 \):
Left side: \( \sqrt{4 - 3(-4)} = \sqrt{16} = 4 \)
Right side: \( -4 \)
\( 4
eq -4 \), so \( n = -4 \) is extraneous.
- For \( n = 1 \):
Left side: \( \sqrt{4 - 3(1)} = \sqrt{1} = 1 \)
Right side: \( 1 \)
Solution is valid.
Step 1: Isolate the rational exponent term
Add 2 to both sides:
\( (x - 25)^{\frac{3}{2}} = 727 + 2 \)
\( (x - 25)^{\frac{3}{2}} = 729 \)
Step 2: Rewrite the exponent
Recall \( a^{\frac{3}{2}} = (\sqrt{a})^3 \), so:
\( (\sqrt{x - 25})^3 = 729 \)
Step 3: Take the cube root of both sides
\( \sqrt{x - 25} = \sqrt[3]{729} \)
\( \sqrt{x - 25} = 9 \)
Step 4: Eliminate the square root
Square both sides:
\( x - 25 = 9^2 \)
\( x - 25 = 81 \)
Step 5: Solve for \( x \)
Add 25 to both sides:
\( x = 81 + 25 = 106 \)
Step 6: Check (optional, since exponent \( \frac{3}{2} \) requires \( x - 25 \geq 0 \), and \( x = 106 \) satisfies this)
Substitute \( x = 106 \):
\( (106 - 25)^{\frac{3}{2}} - 2 = 81^{\frac{3}{2}} - 2 = (9)^3 - 2 = 729 - 2 = 727 \), which matches.
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\( b = 8 \)