Wiskunde Multiple Choice Vraag uit Gricha's Wiskundige Vragenbank

De oplossing van de vergelijking log (x + 30) + log x = 3 is	A. 10
	B. 20
	C. 30
	D. 40
	E. 50

[ 6-6321 - op net sinds 26.4.13-(E)-3.11.2023 ]

Translation in E N G L I S H

The solution of the equation log (x + 30) + log x = 3 is	A. 10
	B. 20
	C. 30
	D. 40
	E. 50

Oplossing - Solution

$https://latex.codecogs.com/png.image?\dpi{110}\log (x+30)+\log x = 3\\\Leftrightarrow \log\left [ (x+30).x \right ] =\log 1000 \;\; \wedge x>0\\\Leftrightarrow x.(x+30)=1000\qquad\qquad \wedge x>0\\\Leftrightarrow x^2+30x-1000 = 0\qquad\quad \wedge x>0\\$