Sorry, i can't see the triangles!
2d+1/6=2d+6 (I distributed the 6 to what was in the parentheses)
2d-2d=6-1/6 (I subtracted 2d from both sides to get the variables on one side and 1/6 from both sides to get the variables by themselves)
0=35/6 (combined like terms)
0=35/6 is an untrue statement so x doesn't exist
So we first minus 6 both sides
7x^2-14x=-6
then we have
A(x^2-2x)=-6
what is A?
hmm (this should be painfully obvous, but if not, here are steps)
7x^2-14x=-6
A(x^2-2x)=-6
7x^2-14x=-6=A(x^2-2x)
7x^2-14x=A(x^2-2x)
undistribute 7
7(x^2-2x)=A(x^2-2x)
divide both sides by (x^2-2x)
7=A
A=7
Answer:
0.8914
Step-by-step explanation:
You want to find the z-values associated with the x-values:
z = (x -μ)/σ
z1 = (57 -90)/12 = -2.75
z2 = (105 -90)/12 = 1.25
Look up these values in a probability table and find the difference of the table values.
p(z < z1) ≈ 0.00298 . . . . from a table or calculator
p(z < z2) ≈ 0.89435 . . . . from a table or calculator
p(57 < x < 105) ≈ 0.89435 -0.00298 = 0.89137 ≈ 0.8914
