You just substitute the value of x in the given equation:
f(x) = 2x^2 - 5
f(-4) = 2 (-4)^2 -5 = 27
f(x) : a name given to the equation
f(-4): refer to the equation when the value of the independent variable x has the value between the brackets.
The tangent of x is defined to be its sine divided by its cosine: tan x = sin x cos x . The cotangent of x is defined to be the cosine of x divided by the sine of x: cot x = cos x sin x .
5 buckets at $2.89 = 5($2.89) = $14.45
10 brushes at $7.91 = 10($7.91) = $79.10
48 towels at $0.36 = 48($0.36) = $17..28
These three added together makes $110.83. This leaves us $144.08-$110.83=$33.25 for the cost of the case of air fresheners.
1/3 + 5/6 + 5/12
1.583333333333333