Question

(x)=3log(x+5)+2 what is the x intercept

Answer 1

Answer:

$\large\boxed{x-intercept=-2+\sqrt[3]{0.01}}$

Step-by-step explanation:

$f(x)=3\log(x+5)+2\to y=3\log(x+5)+2\\\\\text{Domain:}\ x+5>0\to x>-5\\\\\text{x-intercept is for }\ y=0:\\\\3\log(x+5)+2=0\qquad\text{subtract 2 from both sides}\\\\3\log(x+5)=-2\qquad\text{divide both sides by 3}\\\\\log(x+5)=-\dfrac{2}{3}\qquad\text{use the de}\text{finition of logarithm}\\\\(\log_ab=c\iff b^c=a),\ \log x=\log_{10}x\\\\\log(x+2)=-\dfrac{2}{3}\\\\\log_{10}(x+2)=-\dfrac{2}{3}\iff x+2=10^{-\frac{2}{3}}\qquad\text{use}\ a^{-n}=\left(\dfrac{1}{a}\right)^n$

$x+2=\left(\dfrac{1}{10}\right)^\frac{2}{3}\qquad\text{use}\ \sqrt[n]{a^m}=a^\frac{m}{n}\\\\x+2=\sqrt[3]{0.1^2}\qquad\text{subtract 2 from both sides}\\\\x=-2+\sqrt[3]{0.01}\in D$