For solving varible's and for real life questions.
EXAMPLE when you want to figur out what does X eqles
X×4=12 you have to take 12÷4 and that eqles 3
Answer:
Multiply row 1 by
.
Step-by-step explanation:
The augmented matrix of the system of linear equation is described below:
![\left[\begin{array}{cccc}2&1&-1&-8\\0&2&3&-6\\-\frac{1}{2} &1&1&-4\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D2%261%26-1%26-8%5C%5C0%262%263%26-6%5C%5C-%5Cfrac%7B1%7D%7B2%7D%20%261%261%26-4%5Cend%7Barray%7D%5Cright%5D)
Where
, if we need to create
, we need to multiply row 1 by
, that is to say:
![\left[\begin{array}{cccc}1&\frac{1}{2} &-\frac{1}{2} &-4\\0&2&3&-6\\-\frac{1}{2} &1&1&-4\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D1%26%5Cfrac%7B1%7D%7B2%7D%20%26-%5Cfrac%7B1%7D%7B2%7D%20%26-4%5C%5C0%262%263%26-6%5C%5C-%5Cfrac%7B1%7D%7B2%7D%20%261%261%26-4%5Cend%7Barray%7D%5Cright%5D)
Hence, the correct answer is: Multiply row 1 by
.
1 or 5 depends she could fill with just one
Answer: C
Explanation:
Test A.
The left side is
tan(x - π/4) = [tan(x) - tan(π/4)]/[1 + tan(x)*tan(π/4)]
= [tan(x) - 1]/[1 - tan(x)]
= -1
This is not equal to the right side.
Statement A is not an identity.
Test B.
The right side is
sin(x+y)/(sinx siny) = [sin(x)cos(y) + cos(x)sin(y)]/[sin(x)sin(y)]
= cot(y) + cot(x) = 1/tan(y) + 1/tan(x)
= [tanx + tany]/[tan(x)tan(y)]
This is not equal to the left side.
Statement B is not an identity.
Test C.
The right side is
[sin(x)cos(y) - cos(x)sin(y)]/[cos(x)cos(y)]
= sin(x)/cos(x) - sin(y)/cos(y)
= tan(x) - tan(y)
Ths equals the left side.
Statement C is an identity.
Test D.
The left side is
cos(x)cos(π/6) - sin(x)sin(π/6)
= (√3/2)cos(x) - (1/2)sin(x).
The right side is
sin(x)cos(π/3) - cos(x)sin(π/3)
= (1/2)sin(x) - (√3/2)cos(x)
The two sides are not equal.
Statement D is not an identity.