Q. Solve the following quadratic equation for all values of \(x\) in simplest form: \(2(x^{2}-6)-1=-5\).
Answer
Start with \(2(x^2-6)-1=-5\). Then \(2x^2-12-1=-5\), so \(2x^2-13=-5\). Add 5: \(2x^2-8=0\). Divide by 2: \(x^2-4=0\). Thus \(x^2=4\) and \(x=\pm 2\).
Final result: \(x=2\) or \(x=-2\).
Detailed Explanation
Step-by-step solution
- Write the original equation:\(2(x^{2}-6)-1=-5\)
- Apply the distributive property (multiply 2 through the parentheses):\(2\cdot x^{2}-2\cdot 6 – 1 = -5\)
So we get
\(2x^{2}-12-1=-5\)
- Combine like terms on the left side (add -12 and -1):\(-12-1=-13\), therefore
\(2x^{2}-13=-5\)
- Move all terms to one side to obtain a standard quadratic form:Add 5 to both sides:
\(2x^{2}-13+5=0\)
Combine -13 and +5:
\(2x^{2}-8=0\)
- Simplify by dividing both sides by 2 (or factor out 2):Divide by 2:
\(x^{2}-4=0\)
- Factor the difference of squares:\(x^{2}-4=(x-2)(x+2)\)
Set each factor equal to zero:
\(x-2=0\) or \(x+2=0\)
So
\(x=2\) or \(x=-2\)
- Check the solutions (optional verification):For \(x=2\): \(2(2^{2}-6)-1=2(4-6)-1=2(-2)-1=-4-1=-5\) ✓
For \(x=-2\): \(2((-2)^{2}-6)-1=2(4-6)-1=2(-2)-1=-4-1=-5\) ✓
Final answer: \(x=2\) or \(x=-2\)
See full solution
Algebra FAQs
What are the solutions of \(2(x^2-6)-1=-5\)?.
Simplify: \(2(x^2-6)-1=-5\Rightarrow 2x^2-13=-5\Rightarrow 2x^2-8=0\Rightarrow x^2-4=0\). Factor or take roots: \(x=\pm 2\).
How do you simplify the equation step-by-step?
Expand and combine: \(2(x^2-6)-1=2x^2-12-1=2x^2-13\). Move \(-5\): \(2x^2-13+5=0\Rightarrow 2x^2-8=0\). Divide by 2: \(x^2-4=0\).
Can I factor instead of using roots?
Yes. \(x^2-4=(x-2)(x+2)\). Set each factor zero: \(x-2=0 \Rightarrow x=2\), \(x+2=0 \Rightarrow x=-2\).
How would the quadratic formula work here?.
For \(x^2-4=0\) with \(a=1,b=0,c=-4\): \(x=\frac{-0\pm\sqrt{0^2-4(1)(-4)}}{2(1)}=\frac{\pm\sqrt{16}}{2}=\pm 2\).
How can I check the solutions quickly?
Substitute: for \(x=2\), \(2(4-6)-1=2(-2)-1=-5\). For \(x=-2\), same because \(x^2\) same. Both satisfy the original equation.
Are there any extraneous solutions from the steps?.
Are there any extraneous solutions from the steps?.
What is the graph interpretation?
Let \(f(x)=2(x^2-6)-1=2x^2-13\). The horizontal line \(y=-5\) intersects the parabola at \(x=\pm 2\). The parabola vertex is at \((0,-13)\)..
What is the domain of the equation?
The domain is all real numbers, since polynomials are defined for every real \(x\).
Solve quadratic equations with ease
Try our expert AI homework helpers
Try our expert AI homework helpers
252,312+ customers tried
Analytical, General, Biochemistry, etc.
Analytical, General, Biochemistry, etc.