When taking square roots, you can't take square roots of negative roots of negative numbers. So, what will work for the domain of u(x) is what makes u(x) zero or more. We can make an inequality for that.
u(x) ≥ 0.

9x + 27 ≥ 0 by squaring both sides
9x ≥ -27
x ≥ -3
So the domain of the function is when x ≥ -3 is true.
Remember you can do anything to an equation or inequality as long as ou do it to both sides
also, when multiplying by a negative number in an inequality, don't forget to flip the sign
5+5(x+4)<20
minus 5 from both sides
5(x+4)<15
divide both sides by 5
x+4<3
minus 4 from both sides
x<-1
Answer:
0.47x + 7.72
Step-by-step explanation:
We have to create a Linear model using the given two points on the graph. The two points are: (21, 17.5) and (43, 2.75)
The general equation of the line in slope intercept form is
y = mx + c
where m is the slope and c is the y-intercept.
Calculating the slope:

Using the value of m in above equation we get:
y = 0.47x + c
Calculating the y-intercept:
Using any of the given points we can calculate the value of c. Using the point (21, 17.5) in the above equation, we get:
17.5 = 0.47(21) + c
c = 17.5 - 0.47(21)
c = 7.63
Therefore, the equation is:
y = 0.47x + 7.63
Hence option a is the correct answer. The slight change in the value of "c" is because of rounding the value of m to 2 decimal places.
So from the given options, the correct answers is:
y = 0.47x + 7.72
Answer:
x = -20
Step-by-step explanation:
2(x+7) 2x + 20 - 2 = x+4 2x + 8
2x+14 + 2x + 20 - 2 = x + 4 + 2x + 8
4x +32 = 3x + 12
x = -20