It is asking you to find the sum of k^2 - 1 from k=1 to k=4. Since that is only 4 numbers, calculating the sum by hand wouldn’t be that bad.
(1^2 - 1) + (2^2 - 1) + (3^2 - 1) + (4^2 - 1) = 26
The easier way to find the sum is to use a few simple formulas.
When we have a term that is just a constant c, the formula is c*n.
When we have a variable k, the formula is k*n*(n+1)/2.
When we have a squared variable, the formula is k*n*(n+1)*(2n+1)/6.
In this case, we have a squared variable k^2 and a constant of -1.
So plug in n=4 to the formulas:
4*5*9/6 - 1*4 = 26
The answer is 26
Answer:
Percentage profit=40%
Step-by-step explanation:
Cost price=120 Naira
Sold price=168 Naira
Profit=Sold price- cost price
=168-120
=48 Naira
Percentage profit=profit/cost price×100
=48/120×100
=0.4×100
=40%
Percentage profit=40%
Answer:
Non-proportional
Step-by-step explanation:
because it has a y-intercept of 2 in order for it to be proportional its y-intercept should be 0.
Answer:
Step-by-step explanation:
cant remember what this method is called but
change the second equation to be y = something
x + y = 10
y = -x + 10
plug in this y= in the first equation to get x
4x -2(-x + 10) = 4
4x + 2x -20 = 4
6x = 24
x = 4
then plug in the x we found into the original second equation
4 + y = 10
y = 6
so your ordered pair would be (4,6)
hope this helps <3
