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.
7-4x=2-9x the answer is x=1
Answer:
61
Step-by-step explanation:
A + B = 90
6 - 5x + 7 - 2x = 90
13 - 7x = 90
- 7x = 90 - 13
- 7x = 77
- x = 77 / 7
x = - 11
A: 6 - (5 * - 11) = 6 + 55 = 61
B: 7 - (2 * -11) = 7 + 22 = 29
Together they equal 90 as they should.
