Questions on Algebra: Distributive, associative, commutative properties, FOIL answered by real tutors!

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Question 150958This question is from textbook
: My problem is the polynomial function f(x)=0.004x^3-0.15x^2+4.9x + 7. Find the height of the track for x = 30This question is from textbook
: My problem is the polynomial function f(x)=0.004x^3-0.15x^2+4.9x + 7. Find the height of the track for x = 30
Answer by jim_thompson5910(9403) About Me  (Show Source):
You can put this solution on YOUR website!
f(x)=0.004x^3-0.15x^2+4.9x + 7 Start with the given equation.


f(30)=0.004(30)^3-0.15(30)^2+4.9(30) + 7 Plug in x=30.


f(30)=0.004(27000)-0.15(30)^2+4.9(30)+7 Cube 30 to get 27000.


f(30)=0.004(27000)-0.15(900)+4.9(30)+7 Square 30 to get 900.


f(30)=108-0.15(900)+4.9(30)+7 Multiply 0.004 and 27,000 to get 108


f(30)=108-135+4.9(30)+7 Multiply -0.15 and 900 to get -135


f(30)=108-135+147+7 Multiply 4.9 and 30 to get 147


f(30)=127 Combine like terms


So the height is 127 units (you forgot to include the units in the problem) when x=30