Answer:
342in
Step-by-step explanation:
Split up the interval [1, 9] into <em>n</em> subintervals of equal length (9 - 1)/<em>n</em> = 8/<em>n</em> :
[1, 1 + 8/<em>n</em>], [1 + 8/<em>n</em>, 1 + 16/<em>n</em>], [1 + 16/<em>n</em>, 1 + 24/<em>n</em>], …, [1 + 8 (<em>n</em> - 1)/<em>n</em>, 9]
It should be clear that the left endpoint of each subinterval make up an arithmetic sequence, so that the <em>i</em>-th subinterval has left endpoint
1 + 8/<em>n</em> (<em>i</em> - 1)
Then we approximate the definite integral by the sum of the areas of <em>n</em> rectangles with length 8/<em>n</em> and height
:

Take the limit as <em>n</em> approaches infinity and the approximation becomes exact. So we have

Answer:
5a^2 +2a
Step-by-step explanation:
Like terms are ones with the same exponent of x. They can be combined.
3a^2 +2a +2a^2
= (3a^2 +2a^2) +2a
= (3+2)a^2 +2a
= 5a^2 +2a
Answer:
x = -5
Explanation:
4(2x + 10) = 0
[ Simplify both sides of the equation ]
4(2x + 10) = 0
(4)(2x) + (4)(10) = 0 [Distribute]
8x + 40 = 0
[ Subtract 40 from both sides ]
8x + 40 − 40 = 0 − 40
8x = −40
[ Divide both sides by 8 ]
8x / 8 = −40 / 8
x = -5