15.78 is the answer to the qustion that you have asked.
Answer:
f(x) is reflected over the x-axis and vertically scaled by a factor of 3
Step-by-step explanation:
If you compare the two functions, you see that ...
g(x) = -3f(x)
Multiplication by -1 effects a reflection over the x-axis. (All y-values are transformed to their opposite.)
Multiplication by 3 is a vertical scaling by a factor of 3.
Taken together, f(x) is reflected over the x-axis and vertically scaled by a factor of 3.
Cramer's rule works as follows:
x+3y=16
3x+y=8
Then
x=Dx/D
y=Dy/D
where Dx,Dy,D are 2x2 matrices formed from of coefficients and right hand side.
D=
1 3
3 1
=1-9=-8
Dx=matrix D with first column replaced by the vector [16,8]=
16,3
8 1
=16-24
=-8
Dy=matrix D with second column replaced by the vector [16,8]=
1 16
3 8
=8-48
=-40
Therefore
x=-8/-8=1
y=--40/-8=5
Check:
x+3y=1+3(5)=16
3x+y=3(1)+5=8 ok.
12• (0.25) • (-8) ÷ 1/3 • 5
3• (8) ÷ 1/3 • 5
24 • 1/3 • 5
8 • 5
40
Until the second step is ok.
in the third step, she multiplied the 1/3 term instead if dividing it
24 ÷ 1/3 . 5
24 ÷ 5/3
72/5
Prove sinxsin2x+cosxcos2x=cosx
