-9 + 2 = 7
7 + 9 = 16
X = 16
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
The perimeter of the figure to the nearest hundredth is 50.26 cm.
<h3>Perimeter of a figure.</h3>
The perimeter of a figure is the sum of the whole sides of the figure.
The perimeter of the figure can be found as follows:
perimeter of the figure = 12 + 5 + 5 + circumference of the semi circle
circumference of the semi circle = πr
where
perimeter of the figure = 22 + πr
perimeter of the figure = 22 + 3.14(9)
perimeter of the figure = 22 + 28.26
perimeter of the figure = 50.26 cm
learn more on perimeter here: brainly.com/question/11419989
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-2 (t+4)= -2 (t)+-2 (4)= -2t-8