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solve for all possible values of x.\\(\\sqrt{9x + 58} = x + 8\\)\ answe…

Question

solve for all possible values of x.\\(\sqrt{9x + 58} = x + 8\\)\
answer attempt 1 out of 2\
\\(\oplus\\) additional solution \\(\ominus\\) no solution\
\\(x = \square\\)\
submit answer

Explanation:

Step1: Square both sides to eliminate the square root

To solve the equation \(\sqrt{9x + 58}=x + 8\), we first square both sides. Squaring the left side \((\sqrt{9x + 58})^2\) gives \(9x+58\), and squaring the right side \((x + 8)^2\) using the formula \((a + b)^2=a^2+2ab + b^2\) (where \(a = x\) and \(b = 8\)) gives \(x^{2}+16x + 64\). So we get the equation:

$$9x+58=x^{2}+16x + 64$$

Step2: Rearrange into standard quadratic form

Subtract \(9x\) and \(58\) from both sides to set the equation to zero:

$$x^{2}+16x+64 - 9x - 58=0$$

Simplify the like terms: \(16x-9x = 7x\) and \(64 - 58=6\), so the equation becomes:

$$x^{2}+7x + 6=0$$

Step3: Factor the quadratic equation

We need to factor \(x^{2}+7x + 6\). We look for two numbers that multiply to \(6\) (the constant term) and add up to \(7\) (the coefficient of \(x\)). The numbers \(1\) and \(6\) work because \(1\times6 = 6\) and \(1 + 6=7\). So we can factor the quadratic as:

$$(x + 1)(x + 6)=0$$

Step4: Solve for \(x\) using the zero - product property

The zero - product property states that if \(ab = 0\), then either \(a = 0\) or \(b = 0\). So we set each factor equal to zero:

  • If \(x+1 = 0\), then \(x=-1\).
  • If \(x + 6=0\), then \(x=-6\).

Step5: Check for extraneous solutions

We need to check these solutions in the original equation because squaring both sides can introduce extraneous solutions.

  • For \(x=-1\):

Left side: \(\sqrt{9(-1)+58}=\sqrt{-9 + 58}=\sqrt{49}=7\)
Right side: \(-1 + 8=7\)
Since the left side equals the right side, \(x=-1\) is a valid solution.

  • For \(x=-6\):

Left side: \(\sqrt{9(-6)+58}=\sqrt{-54 + 58}=\sqrt{4}=2\)
Right side: \(-6 + 8=2\)
Wait, wait, let's recalculate the left side for \(x = - 6\): \(9\times(-6)+58=-54 + 58 = 4\), \(\sqrt{4}=2\), and the right side is \(-6 + 8 = 2\). Wait, but earlier when we squared, we might have made a mistake? Wait no, let's check again. Wait, no, when \(x=-6\), original equation: \(\sqrt{9\times(-6)+58}=\sqrt{-54 + 58}=\sqrt{4}=2\), and \(x + 8=-6 + 8 = 2\). But wait, let's check the domain of the square root. The expression inside the square root \(9x + 58\) must be non - negative. For \(x=-6\), \(9\times(-6)+58=4\geq0\), and for \(x=-1\), \(9\times(-1)+58 = 49\geq0\). Wait, but let's check the original equation again for \(x=-6\): \(\sqrt{9x + 58}=\sqrt{9\times(-6)+58}=\sqrt{4}=2\), and \(x + 8=-6 + 8 = 2\). So both seem to work? Wait, no, wait I made a mistake in the factoring step? Wait, no, the quadratic was \(x^{2}+7x + 6=(x + 1)(x + 6)\), that's correct. Wait, but let's re - check the squaring step. Original equation: \(\sqrt{9x + 58}=x + 8\). For \(x=-6\), the right side is \(x + 8=2\), and the left side is \(\sqrt{9x + 58}=\sqrt{4}=2\). So \(x=-6\) also works? Wait, but when I first calculated, I thought maybe there was a mistake, but according to the calculations, both work. Wait, but let's check the original problem again. Wait, the original equation is \(\sqrt{9x + 58}=x + 8\). Let's check \(x=-6\) again:

Left: \(\sqrt{9*(-6)+58}=\sqrt{-54 + 58}=\sqrt{4}=2\)

Right: \(-6 + 8=2\). So it is valid. Wait, but maybe I made a mistake in the initial thought about extraneous solutions. But let's check the problem again. Wait, the user's problem is to solve for all possible values of \(x\). So both \(x=-1\) and \(x=-6\)? Wait, no, wait when \(x=-6\), let's check the domain of the square root: \(9x + 58\geq0\), \(9x\geq - 58\), \(x\geq-\frac{58}{9}\approx - 6.44\). Both \(x=-6\) (which is greater than \(-\frac{58}{9}\)) and \(x=-1\) (also greater than \(-\frac{58}{9}\)) are in the domain. Wait, but…

Answer:

The solutions are \(x=-1\) and \(x=-6\). If we consider the first solution (for the first attempt), we can write \(x=-1\) (or \(x=-6\), but \(x=-1\) is also valid).