Answer: x = {-4, 5}
<u>Step-by-step explanation:</u>
log (10x + 200) = log (x²) + log (10)
log (10x + 200) = log (10x²)
10x + 200 = 10x²
0 = 10x² - 10x - 200
0 = x² - x - 20
0 = (x - 5)(x + 4)
0 = x - 5 0 = x + 4
x = 5 x = -4
Check for extraneous solutions:
10x + 200 > 0 x² > 0
x = 5 10(5) + 200 > 0 (5)² > 0 both are satisfied
x = -4 10(-4) + 200 > 0 (-4)² > 0 both are satisfied
Both solutions are valid!
Answer:
21
Step-by-step explanation:
Pythagoras
28^2-19^2= 423
Square root of 423 = 20.5669638
Answer = 20.5669638
To reverse a percentage decrease you divide it by the decrease (+ 100%)
For example we will pick the number, 100, which is decreased by 15% to 85.
To make 85 back to 100 we divide it by the decrease (1-0.15):
85 / 0.85 = 100
To find out how much 85 increased to get back to 100, we do:
15 / 85 = 0.1765 = %17.65
15 is the reduction/difference, and 85 is the with reduction total.
Because percentages stay the same, this is applicable to any numbers, from this, we know that whenever something is reduced by 15% - when restored to it's original is increased by %17.65
The answer is %17.65
