Respuesta :

Answer:

x = - 5, x = 2

Step-by-step explanation:

Using the rules of logarithms

log x - log y = log ([tex]\frac{x}{y}[/tex] )

[tex]log_{b}[/tex] x = n ⇔ x = [tex]b^{n}[/tex]

note that log x = [tex]log_{10}[/tex] x

Given

log (x² + 3x) - log10 = 0, then

log([tex]\frac{x^2+3x}{10}[/tex] ) = 0, thus

[tex]\frac{x^2+3x}{10}[/tex] = [tex]10^{0}[/tex] = 1 ( multiply both sides by 10 )

x² + 3x = 10 ( subtract 10 from both sides )

x² + 3x - 10 = 0 ← in standard form

(x + 5)(x - 2) = 0 ← in factored form

Equate each factor to zero and solve for x

x + 5 = 0 ⇒ x = - 5

x - 2 = 0 ⇒ x = 2

Solution is x = - 5, x = 2

Answer:

The equation has the solution(s) x = - 5, and x = 2

Step-by-step explanation:

Let's start by adding log(10) to either side of the equation --- (1)

[tex]\log _{10}\left(x^2+3x\right)-\log _{10}\left(10\right)+\log _{10}\left(10\right)=0+\log _{10}\left(10\right)[/tex]

= [tex]\log _{10}\left(x^2+3x\right)=\log _{10}\left(10\right)[/tex]

If you recall, one property proves that [tex]\log _{10}\left(10\right):\qu 1[/tex]. We can substitute this value back into the simplified equation --- (2)

[tex]\log _{10}\left(x^2+3x\right)=1[/tex]

We can also apply the logarithmic definition, If logₐ(b) = c then b = aᶜ. Using this definition we receive a further simplified equation --- (3)

[tex]x^2+3x=10^1[/tex]

[tex]x^2+3x=10[/tex]

Solving for the expression we receive the solution(s) x = 2, and x = - 5, our first option.

Note : The first solution is correct, but I wanted to take a slightly different approach

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