These techniques for elimination are preferred for 3rd order systems and higher. They use "Row-Reduction" techniques/pivoting and many subtle math tricks to reduce a matrix to either a solvable form or perhaps provide an inverse of a matrix (A-1)of linear equation AX=b. Solving systems of linear equations (n>2) by elimination is a topic unto itself and is the preferred method. As the system of equations increases, the "condition" of a matrix becomes extremely important. Some of this may sound completely alien to you. Don't worry about these topics until Linear Algebra when systems of linear equations (Rank 'n') become larger than 2.
Answer:
x=-1/2
Step-by-step explanation:
2x+2=4x+3
-1=2x
x=-1/2
Answer:

Step-by-step explanation:
To get the equation in the slope-intercept form first, put the equation in slope-point form using the information given. The slope-point form is
. Then solve for y.
Distribute -3 to
,

Then, add -2 to both sides,

This is your final answer; the slope is -3 and the y-intercept is 4. There are also a few other ways to solve but I find this the easiest.
Answer:
D
Step-by-step explanation:
Its D because A is all 90 degrees
Not C because all 90
Answer:
The probability is 0.9909.
Step-by-step explanation:
Test statistic (z) = (sample mean - population mean) ÷ (sd/√n)
sample mean = 290 days
population mean = 298 days
sd = 22 days
n = 42
z = (290 - 298) ÷ (22/√42) = -8 ÷ 3.395 = -2.36
The cumulative area of the test statistic is the probability that the mean gestation period is less than 290 days. The cumulative area is 0.9909. Therefore the probability is 0.9909.