Which if the following is not a characteristic of both observational studies and experiments
a . the subjects are observed, and their behavior is recorded
b. results are not used to prove cause and effect
c data are collected about population
d. the researcher exercises direct control over at least one variable

infinitely many solutions

step-by-step explanation:

we have been given the equation;

2(2x + 3) = -4 + 2(2x + 5)

we need to determine the value of x.

2(2x + 3), we expand this expression to obtain 4x + 6

similarly 2(2x + 5) will become 4x + 10

now we have;

4x + 6 = -4 + 4x + 10

4x + 6 = 4x + 10 - 4

4x + 6 = 4x + 6

the expression on the left hand side is identical to the one on the right hand side. therefore, we are looking at just a single straight line whose equation is;

y = 4x + 6

consequently, we shall have infinitely many solutions

b

step-by-step explanation:

u take $75 minus $60.the anwer/original($75)multiply by 100

answer: the is put the 450

step-by-step explanation:

zero

step-by-step explanation:

f(2)= x-2

plug in the 2 in the "x"

f(2)=2-2

f(2)=0