Step-by-step explanation:
Let the two-digit number is 
<u>This can be written as:</u>
- 10x + y, where 1 ≤ x ≤ 9 and 0 ≤ y ≤ 9
<u>The difference between the number and product of its digits is:</u>
<u>Rewrite this as below:</u>
d = 10x - xy + y - 10 + 10 =
x(10 - y) - (10 - y) + 10 =
(x - 1)(10 - y) + 10
<u>We see that:</u>
- 0 ≤ x - 1 ≤ 8 according to the condition given above
- 1 ≤ 10 - y ≤ 10 again according to the condition given above
<u>The value of d is then:</u>
- 0 + 10 ≤ d ≤ 8*10 + 10
- 10 ≤ d ≤ 90
<h3>Proved</h3>
Answer:
i)W = 2500 / T
ii) W = 500 Tons
iii) grad W(10°) = - 25î
iv) The formulation is not practical
Step-by-step explanation:
i) Write an equation describing the use of coal
As use of coal is inversely proportional to the average monthly temperature
if W is use of coal in tons/per month then
W(t) = k / T where k is a constant of proportionality and T is the average temperature in degrees. We have to determine k from given conditions
k = ?? we know that when T = 25° W = 100 tons the by subtitution
W = k/T 100 = k /25 k = 2500 Tons*degree
Then final equation is:
W = 2500 / T
ii) Find the amount of coal when T = 5 degrees
W = 2500 / 5
W = 500 Tons
iii)
The inverse proportionality implies that W will decrease as T increase.
The vector gradient of W function is:
grad W = DW(t)/dt î
grad W = - 2500/T² î
Wich agrees with the fact that W is decreasing.
And when T = 100°
grad W(10°) = - 2500/ 100 î ⇒ grad W(10°) = - 25î
iv) When T = 0 The quantity of coal tends to infinite and the previous formulation is not practical
First you subtract the two equations
x^2-2x+3-6x
You simplify that and get
x^2+4x+3 = 0
Now we solve using the quadratic formula.
We get x = -1 and x = -3.
Now we find the y values by plugging the x values into the equation.
f(x) is the same as y.
y = (-1)^2 - 2(-1) + 3
y = 1+2+3
y = 6
Now for the other x value.
y = (-3)^2 - 2(-3) + 3
y = 9+9
y = 18
So the two ordered pairs are (-1,6) and (-3,18)
Answer:
m = -1
Step-by-step explanation:
12 times the number is 12m
17 less than that is 12m -17.
23 less than 6 times the number is 6m-23.
These expressions are said to be the same:
12m -17 = 6m -23
6m -17 = -23 . . . . . . . . subtract 6m from both sides
6m = -6 . . . . . . . . . . add 17 to both sides
m = -1 . . . . . . . . . divide both sides by 6
The value of m is -1.
