A/2=b/3
b/a
a=2/3b
b=3/2a
4b/9a
Answer:
12-x
Step-by-step explanation:
Answer:
the equation of the line is y = -3x - 6
Step-by-step explanation:
Note that since (0, -6) is the y-intercept, we can write the slope-intercept equation of the line as y = mx - 6. The other given point is (-2, 0) (which happens to be the x-intercept also). Starting with y = mx - 6, replace y with 0 and x with -2:
0 = m(-2) - 6. We now solve this for the slope, m: 0 = -2m - 6 becomes
2m = -6, or m = -3.
With m = -3 and b = -6, the equation of the line is y = -3x - 6
8.9
The equation for the grain size is expressed as the equality:
Nm(M/100)^2 = 2^(n-1)
where
Nm = number of grains per square inch at magnification M.
M = Magnification
n = ASTM grain size number
Let's solve for n, then substitute the known values and calculate.
Nm(M/100)^2 = 2^(n-1)
log(Nm(M/100)^2) = log(2^(n-1))
log(Nm) + 2*log(M/100) = (n-1) * log(2)
(log(Nm) + 2*log(M/100))/log(2) = n-1
(log(Nm) + 2*log(M/100))/log(2) + 1 = n
(log(33) + 2*log(270/100))/log(2) + 1 = n
(1.51851394 + 2*0.431363764)/0.301029996 + 1 = n
(1.51851394 + 0.862727528)/0.301029996 + 1 = n
2.381241468/0.301029996 + 1 = n
7.910312934 + 1 = n
8.910312934 = n
So the ASTM grain size number is 8.9
If you want to calculate the number of grains per square inch, you'd use the
same formula with M equal to 1. So:
Nm(M/100)^2 = 2^(n-1)
Nm(1/100)^2 = 2^(8.9-1)
Nm(1/10000) = 2^7.9
Nm(1/10000) = 238.8564458
Nm = 2388564.458
Or about 2,400,000 grains per square inch.
