Answer:
450
Step-by-step explanation:
75+75+75+75+75+75
At the 2/8 part, just use the quadratic formula. If you use it, you should get the other two zeroes:
The answer is most likly to be B.
Y = x^2 - 8x + 7
a) y-intercept
The y-intercept is the point where it crosses the y axis so x would 0.
So putting in 0 for x:
y = x^2 - 8x + 7
y = 0^2 - 8(0) + 7
y = 0 - 0 + 7
y = 7
The y intercept is at the point (0,7).
b)
The zeroes are the points where it crosses the x axis so it’s when the y is set to 0.
0 = x^2 - 8x + 7
Since it’s a quadratic equation we have to factor it. We fill in 2 numbers that add to -8 and multiplied to equal 7.
(x +____)(x+ ____)
The 2 numbers are 7 and -1 because -1*-7=7 and -7+(-1)=-8. So:
0 = (x-7)(x-1)
So now we have x-7 and x-1 equaling some quantity. If either of those happens to equal zero, it makes the whole equation 0, because (x-7)0=0 and 0(x-1)=0
So we can set each of it separately to 0 to solve for x.
x-7=0
x= 7
x-1=0
x= 1
The zeroes are at the points (1, 0) and (7, 0)
C.
The Vertex Form of a Quadratic is:
y = a(x-h)^2 + k. And the vertex is (h, k)
y = x^2 - 8x + 7
y - 7 = x^2 - 8x
We want to complete the square by adding some number to both sides of the equation so that when we factor it we are going to get (x-a)(x-a).
So take half of 8 to get two equal numbers that would be our “a”. 8/2=4 so we want (x - 4)(x- 4).
(x-4)(x-4) multiplies out to x^2 - 8 + 16.
continuing,
y - 7 = x^2 - 8x
Add 16 to both sides.
y - 7 + 16 = x^2 - 8x + 16
y + 9 = (x-4)(x-4)
y + 9 = (x-4)^2
y = (x-4)^2 - 9 is the vertex form.
The vertex is at the point (4, -9). So the axis of symmetry is at the line x = 4.
D. The vertex is solved in C as the point (-4, -9).
