Answer:
x = 10
Step-by-step explanation:
Using the rules of logarithms
• log x + log y ⇔ log(xy)
• log
⇔ n log x
• log x = log y ⇒ x = y
Given
ln20 + ln5 = 2 lnx , then
ln(20 × 5) = ln
ln 100 = ln
, hence
x² = 100 ( take the square root of both sides )
x = 10
Answer:

Step-by-step explanation:

Geometric formula sequence: 
(where
is the first term of the sequence and
is the common ratio)
To find the common ratio, divide one of the terms by the previous term:

From inspection, 
Therefore, 
Answer:
r = i + j + (-2/3)(3i - j)
Step-by-step explanation:
Vector Equation of a line - r = a + kb ; where r is the resultant vector of adding vector a and vector b and k is a constant
if a = i + j ; b = t(3i - j) and r = -i +s(j)
for this to be true all the vector components must be equal
summing i 's
i + 3ti = -i; then t = -2/3
j - tj = sj; then s = 1-t; substitue t; s=1+2/3 = 5/3
so r = i + j + (-2/3)(3i - j) which will symplify to -i + 5/3j
Answer:
perpendicular
Step-by-step explanation:
start but putting each line into the standard line format
2x-y=-5
-y=-2x-5
y=2x+5
x+2y=-6
2y=-x-6
y=-(1/2)x-3
if lines are parallel the slopes would be the same. 2 is not equal to -1/2
if lines are perpendicular the slope of one would be the opposite inverse of the other.
negative inverse of 2 = - (1/2)
so the lines are perpendicular
The value of x in that equation is -12