Carry out the mult.: f(x) = -[x^2 - 21x + 9x - 189]
Combine like terms: f(x) = -[x^2 - 12x - 189]
Eliminate the brackets [ ]: f(x) = -x^2 + 12x + 189
Identify coefficients a, b and c: a= -1, b=12, c=189
The equation of the axis of symmetry is x = -b/(2a), which here equals
x = -(12)/[2(-1)], or x = 6
This is also the x-coordinate of the vertex. Plug x=6 into the original equation to calculate the y-coordinate.
Answer: 1. x=2
2. x=5
3.x=-3
Isolate the variable by dividing each side by factors that don't contain the variable.
Move all terms not containing x to the right side of the equation.
Hope this helped
17+x=57.
So, subtract 17 from both sides
X=40
4/5 recommend, so about 4/5(120) = 96 doctors recommend the brand.
