Answer:
x = 99 degrees.
Step-by-step explanation:
The angle in the triangle adjacent to 123 = 180 - 123 = 57 degrees.
m < x = 42 + 57 = 99 degrees. ( by the external angle of triangle theorem).
Answer:
1. 
2. 
5. (q+3r)(q^2-3qr+9r^2)
7. x= - 4/7, 1/9
See below for additional problems and help.
Step-by-step explanation:
To factor polynomials, look for patterns and greatest common factors. When you remove these factors, write the factor and what remains.
For example:

Notice the term
is left and is the term when the expression is divided by -m.
2. Factor by grouping is similar. Pull out factors within pairs of term. Separate the terms by parenthesis. If the quantities in the [parenthesis are the same, the factoring has been successful.

Notice that (2w+7c) is the same. The factoring is complete. The factors are:

3 - 6 is similar using specific forms for factoring. To find the forms, look in your notes or at resources on online. Here is one example.
4. A sum of cubes has the form
.
To use this form, take the cube root of each term. a = q and b=3r.
The factors are 
7-9 all involve factoring and then solving. You solve by setting the factors equal to 0.
7. (7x+4)(9x-1) = 0
(7x+4) = 0 (9x-1)=0
7x=-4 9x = 1
x= - 4/7 x = 1/9
X + 4y = 9 Convert to slope / intercept form:-
y = (-1/4)x + 9/4
so the line perpendicular to this will have a slope -1 /(-1/4) = 4
so our equation will be y - y1 = 4(x - x1) where x1y1 is a point on the line.
x1 = 8 and y1 = -3:-
y - -3 = 4(x - 8)
y = 4x - 35
-4x + y = -35 is the answer
ANSWER
The constant of variation is 6.
EXPLANATION
The inverse variation equation is:

We want to find the constant of variation, when x=-3 and y=-2.
We substitute the values for x and y to get,

Multiply out the left hand keeping in mind that negative times negative yields a positive result.
This implies that;

Hence the constant of variation is 6.
What is the standard deviation of the data set?
6, 4, 9, 5, 5, 4, 5
Round the answer to the tenths place.What is the standard deviation of the data set?
6, 4, 9, 5, 5, 4, 5
Round the answer to the tenths place.
Step-by-step explanation:
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