A $500 TV is marked up 60%. Sales tax is 8.5%. How much will is cost to buy the TV?
1 answer:
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Answer:
(a) 120 square units (underestimate)
(b) 248 square units
Step-by-step explanation:
<u>(a) left sum</u>
See the attachment for a diagram of the areas being summed (in orange). This is the sum of the first 4 table values for f(x), each multiplied by 2 (the width of the rectangle). Quite clearly, the curve is above the rectangle for the entire interval, so the rectangle area underestimates the area under the curve.
left sum = 2(1 + 5 + 17 + 37) = 2(60) = 120 . . . . square units
<u>(b) right sum</u>
The right sum is the sum of the last 4 table values for f(x), each multiplied by 2 (the width of the rectangle). This sum is ...
right sum = 2(5 +17 + 37 +65) = 2(124) = 248 . . . . square units
Answer:
A and C
Step-by-step explanation:
solving the equations
A
x² - 4 = 0 ( add 4 to both sides )
x² = 4 ( take square root of both sides )
x = ± = ± 2 ← required solution
B
x² = - 4 ← has no real solutions
C
4x² = 16 ( divide both sides by 4 )
x² = 4 ( take square root of both sides )
x = ± = ± 2 ← required solution
D
2(x - 2)² = 0 , then
x- 2 = 0 ( add 2 to both sides )
x = 2 ← not the required solution