7) Certainly there is a typo in the statement, just see that the expression of item (ii) is different from that of item (i). Probably the correct expression is:

. With this consideration, we can continue.
(i) Let E the expression that we are analyzing:

Since (x-1)² is a perfect square, it is a positive number. So, E is a result of a sum of two positive numbers, 2(x-1)² and 3. Hence, E is a positive number, too.
(ii) Manipulating the expression:

So, it's the case when E=0. However, E is always a positive number. Then, there is no real number x that satisfies the expression.
8) Let E the expression that we want to calculate:

Multiplying by (2-1) in the both sides:

Repeating the process, we obtain:
Let V, be the rate in still water and let C = rate river current
If the boat is going :
upstream, its rate is V-C and if going
downstream, its rate is V+C,
But V = 5C, then
Upstream Rate: 5C - C = 4 C
Downstream rate: 5C+C = 6C
Time = distance/Rate, (or time = distance/speed) , then:
Upstream time 12/4C and
Downstream time: 12/.6C
Upstream time +downstream time:= 2h30 ' then:
12/4C + 12/.6C = 2.5 hours
3/C + 2/C = 5/2 (2.5 h = 5/2)
Reduce to same denominator :
5C = 10 and Rate of the current = 2 mi/h
Answer:
C) a positive correlation
Step-by-step explanation:
<em>More people ⇒ Longer time</em> is a positive correlation between those variables. However, <em>longer time</em> is not the desired outcome.
Rather, <em>shorter time</em> is the desired outcome. The correlation between <em>more people</em> and <em>shorter time</em> is negative. In order to compute that correlation numerically, one would have to define a function that would give a numerical value for "shorter time" that would model the goodness of outcome as time gets shorter.
Answer:
252
Step-by-step explanation:
To be divisible by 3, it's digits have to add to a number that is a multiple of 3.
To be divisible by 4 its last 2 digits have to be divisible by 3.
So let's start with 1x1 which won't work because 1x1 is odd. so let's go to 2x2 and see what happens.
212 that's divisible by 4 but not 3
222 divisible by 3 but not 4
232 divisible by 4 but not 3
242 not divisible by either one.
252 I think this might be your answer
The digits add up to 9 which is a multiple of 3 and the last 2 digits are divisible by 4