(a-b) X (a+b)
= aXa - bXa +aXb -bXb (distributing)
Now, cross product of a vector with itself = 0
so, aXa = 0, bXb = 0
Also, aXb = - bXa
so,
(a-b) X (a+b) = 0 + aXb + aXb + 0
= 2aXb
hence, proved :)
Answer:
given us,
(x1y1) = (4,6)
(x2y2)= (1,10)
here
slope= (y2-y1)/ (x2-x1)
= (10-6)/ (1-4)
= 4/ (-3)
Step-by-step explanation:
4/ (-3)
Answer:
3
Step-by-step explanation:
Answer:
-1/6
Step-by-step explanation:
flip the slope

becomes

now the slope is going down so it becomes negative
= -1/6
Let's say the number of days library book is late is X, and the total fee is Y.
Liability charges $0.30 dollars as a fee for being 1 day late,
For being 1 day late, fee charge is: 1* $0.30
So, for X days the charge would be: X*$0.30.
Total charge for being X days late is Y, Which means: Y= 0.30 * X.
Now We would have to check all the viable solutions in the answer to see if they satisfy the equation Y= 0.30 * X
Option one(-3, -0.9) and two (-2.5, -0.75) Would not be a viable solution because the value of number of days can not be negative and in option one and two, value of days -3 and -2.5 is negative.
Option three(4.5, 1.35) can not be correct because library charges fee for a full day so the number for days would be a whole number. Library would not charge for 4.5 days, they would either charge of 4 days or 5 days because 4.5 is not an whole number.
Option four(8, 2.40) is the correct answer because it satisfies our equation;
Y= 0.30 * X
2.40= 0.30 * 8
2.40 = 2.40.
Fourth option (8, 2.40) is the only viable solution to this question.