Please help 8th grade math!

Y=-x^2+6x-4 Find the Axis of Symmetry and the Vertex, Also solve the whole equation.

Inessa [10]

Answer:

1. Axis of symmetry: x = 3

2. Vertex: (3,5)

3. Solution of the equation:

x-intercepts:

$(3-\sqrt{5},0) \\\\(3+\sqrt{5},0)$

y-intercept: (0, -4)

Explanation:

1. Equation:

$y=-x^2+6x-4$

2. Axis of symmetry:

That is the equation of a parabola, whose standard form is:

$y=ax^2+bx+c$

Where:

$a=-1;b=6;c=-4$

The axis of symmetry is the vertical line with equation:

$x=-b/2a$

Substitute $a=-1,\text{ and }b=6$

$x=-6/[(2)(-1)]=-6/(-2)=3$

Thus, the axis of symmetry is:

$x=3$

3. Vertex

The x-coordinate of the vertex is equal to the axys of symmetry, i.e x = 3.

To find the y-xoordinate, substitute this value of x into the equation for y:

$y=-x^2+6x-4\\\\y=-(3)^2+6(3)-4=-9+18-4=5$

Therefore, the vertex is (3, 5)

4. Find the x-intercepts

The x-intercepts are the roots of the equation, which are the points wher y = 0.

$y=-x^2+6x-4=0$

Use the quadratic equation:

$x=\frac{-b\pm \sqrt{b^2-4ac} }{2a} \\\\x=\frac{-6\pm\sqrt{(-6)^2-4(-1)(-4)} }{2(-1)}\\\\x_1=3-\sqrt{5} \\\\x_2=3+\sqrt{5}$

5. Find the y-intercept

The y-intercet is the value of y when x=0:

$y=-x^2+6x-4\\\\y=-(0)^2+6(0)-4=-4$

7 0

3 years ago

A manufacturer determines that the number of toys it can sell is given by the formula

otez555 [7]

Answer:

The price where the manufacture sells the maximum number of toys is $20

Step-by-step explanation:

The given equation for that represents the number of toys the manufacturer can sell is given as follows;

T = -4·p² + 160·p - 305

Where;

p = The price of the toys in dollars

At the point where the manufacture sells the maxim number of toys on the graph of the equation T = -4·p² + 160·p - 305, which is the top of the graph, the slope = 0

Therefore, at the maximum point;

The slope = 0 = dT/dp = d(-4·p² + 160·p - 305)/dp = -8·p + 160

∴ -8·p + 160 = 0

160 = 8·p

8·p = 160

p = 160/8 = 20

The price where the manufacture sells the maximum number of toys is = p = 20 dollars

4 0

2 years ago

What is the sum of 43 and z is equal to 72.98.

lisov135 [29]

Answer:

x + 43 = 72.98

- 43 - 43

x = 29.98

Step-by-step explanation:

3 0

3 years ago

A tree that is 14 feet tall casts a shadow that is 30 feet long. Find the angle of the elevation from the top of the shadow to t

Umnica [9.8K]

Let x = angle we must find

tan x = 14/30

arctan(tan x) = arctan(14/30)

x = 25.0168934781

Answer: 25 degrees

8 0

3 years ago

Which of the following is the radical expression of a to the four ninths power ?

LuckyWell [14K]

Given expression in exponential form : $a^{\frac{4}{9} }$ .

We need to convert it into radical form.

Please note: When we convert an exponential to radical form, the top number goes in the exponent of the term and bottom number of the fraction goes in the radical sign to make it nth radical.

We can apply following rule:

$(a)^{\frac{m}{n}}= \sqrt[n]{x^m}$ .

Therefore,

$a^{\frac{4}{9} }= \sqrt[9]{a^4}$ .

Therefore, correct option is : D. ninth root of a to the fourth power.

6 0

3 years ago