Solve: [tex]\sqrt{3a - 5} = a - 3[/tex]

A. [tex]a = -2, -7[/tex]
B. [tex]a = 7[/tex]
C. [tex]a = 1[/tex]
D. [tex]a = 2, 7[/tex]



Answer :

Sure! Let's solve the equation [tex]\(\sqrt{3a - 5} = a - 3\)[/tex] step-by-step.

Step 1: Start with the given equation.
[tex]\[ \sqrt{3a - 5} = a - 3 \][/tex]

Step 2: To eliminate the square root, square both sides of the equation.
[tex]\[ (\sqrt{3a - 5})^2 = (a - 3)^2 \][/tex]
Simplify both sides:
[tex]\[ 3a - 5 = a^2 - 6a + 9 \][/tex]

Step 3: Rearrange the equation to bring all terms to one side, setting it equal to zero.
[tex]\[ a^2 - 6a + 9 - 3a + 5 = 0 \][/tex]
Combine like terms:
[tex]\[ a^2 - 9a + 14 = 0 \][/tex]

Step 4: Solve the quadratic equation [tex]\(a^2 - 9a + 14 = 0\)[/tex]. To do this, we can factor the quadratic expression.
[tex]\[ a^2 - 9a + 14 = (a - 7)(a - 2) = 0 \][/tex]

Step 5: Set each factor equal to zero and solve for [tex]\(a\)[/tex].
[tex]\[ a - 7 = 0 \quad \text{or} \quad a - 2 = 0 \][/tex]
[tex]\[ a = 7 \quad \text{or} \quad a = 2 \][/tex]

Step 6: Check each solution in the original equation [tex]\(\sqrt{3a - 5} = a - 3\)[/tex] to verify if it holds true.

- For [tex]\(a = 7\)[/tex]:
[tex]\[ \sqrt{3(7) - 5} = 7 - 3 \][/tex]
[tex]\[ \sqrt{21 - 5} = 4 \][/tex]
[tex]\[ \sqrt{16} = 4 \][/tex]
[tex]\[ 4 = 4 \quad \text{(True)} \][/tex]

- For [tex]\(a = 2\)[/tex]:
[tex]\[ \sqrt{3(2) - 5} = 2 - 3 \][/tex]
[tex]\[ \sqrt{6 - 5} = -1 \][/tex]
[tex]\[ \sqrt{1} = -1 \][/tex]
[tex]\[ 1 \neq -1 \quad \text{(False - this is not a valid solution)} \][/tex]

Therefore, the only valid solution is [tex]\(a = 7\)[/tex].

Thus, the solution to the equation [tex]\(\sqrt{3a - 5} = a - 3\)[/tex] is:
[tex]\[ \boxed{7} \][/tex]