Find the value of the expression

Use the Quadratic Formula to solve the equation 4x^2−7=4x.

tino4ka555 [31]

Answer:

$\large\boxed{x=\dfrac{1}{2}-\sqrt2\ or\ x=\dfrac{1}{2}+\sqrt2}$

Step-by-step explanation:

$\text{The quadratic formula of}\ ax^2+bx+c=0:\\\\x=\dfrac{-b\pm\sqrt{b^2-4ac}}{2a}$

$\text{We have:}\\\\4x^2-7=4x\qquad\text{subtract}\ 4x\ \text{from both sides}\\\\4x^2-4x-7=0\\\\a=4,\ b=-4,\ c=-7\\\\b^2-4ac=(-4)^2-4(4)(-7)=16+112=128\\\\\sqrt{b^2-4ac}=\sqrt{128}=\sqrt{64\cdot2}=\sqrt{64}\cdot\sqrt2=8\sqrt2\\\\x=\dfrac{-(-4)\pm8\sqrt2}{(2)(4)}=\dfrac{4\pm8\sqrt2}{8}\qquad\text{simplify by 4}\\\\x=\dfrac{1\pm2\sqrt2}{2}\to x=\dfrac{1}{2}\pm\sqrt2$

6 0

3 years ago

For the straight line defined by the points (4,57) and (6,91) , determine the slope ( m ) and y-intercept ( ???? ). Do not round

Ksivusya [100]

$\bf (\stackrel{x_1}{4}~,~\stackrel{y_1}{57})\qquad (\stackrel{x_2}{6}~,~\stackrel{y_2}{91}) \\\\\\ \stackrel{slope}{m}\implies \cfrac{\stackrel{rise} {\stackrel{y_2}{91}-\stackrel{y1}{57}}}{\underset{run} {\underset{x_2}{6}-\underset{x_1}{4}}}\implies \cfrac{34}{2}\implies 17 \\\\\\ \begin{array}{|c|ll} \cline{1-1} \textit{point-slope form}\\ \cline{1-1} \\ y-y_1=m(x-x_1) \\\\ \cline{1-1} \end{array}\implies y-\stackrel{y_1}{57}=\stackrel{m}{17}(x-\stackrel{x_1}{4})\implies y-57=17x-68$

$\bf y=17x-11\impliedby \begin{array}{|c|ll} \cline{1-1} slope-intercept~form\\ \cline{1-1} \\ y=\underset{y-intercept}{\stackrel{slope\qquad }{\stackrel{\downarrow }{m}x+\underset{\uparrow }{b}}} \\\\ \cline{1-1} \end{array}\qquad \qquad \begin{cases} \stackrel{slope}{17}\\\\ \stackrel{y-intercept}{(0,-11)} \end{cases}$

4 0

3 years ago

HELP ME PLEASE !!!!!!

Lunna [17]

Answer:

A

Step-by-step explanation:

The answer is (a) because that value is the y intercept meaning that it will be the value for price at the beginning of the time frame... in this case in January 2013 which is the beginning of the year.

Hope you find this helpful.

6 0

3 years ago

A toy baseball bat comes with 3 plastic balls. The balls are in a box that is a rectangular solid. The box is just big enough to

vodomira [7]

Answer:

31.4 in³

Step-by-step explanation:

The box is just big enough to hold the 3 balls, so it must have a length 6 times the radius of each ball, a width 2 times the radius, and a height 2 times the radius.

The volume of the box is:

V = (6r)(2r)(2r)

V = 24r³

The volume of the 3 balls is:

V = 3 (4/3 π r³)

V = 4πr³

So the volume of the air is:

V = 24r³ − 4πr³

V = (24 − 4π) r³

Since r = 1.4 inches:

V = (24 − 4π) (1.4 in)³

V ≈ 31.4 in³

5 0

3 years ago

Solve for x 2 + 2 * x = 10

inysia [295]

Answer:

6

Step by step explanation:

2 + 2 * x = 10

2x+2=10

2x+2−2=10−2

Therefore, x = 6

7 0

3 years ago