All categories

2 years ago

Please help fast ^^

1 answer:

7 0

The discriminante :
b^2-4ac

1^2 - 4 * -2 * -28 = 1 - 224 = -223

When the discriminant (b^2-4ac) is less than 0, the equation had no real solutions.

-223<0, so, 2x^2+x-28 = 0 has no real solutions.

Hope that helps :)

You might be interested in

Plz help I need to know how many bags of snacks they bought in all

spin [16.1K]

Answer:

7x - 2

Step-by-step explanation:

let x be the number of bags of chips, then

3x is the number of bags of pretzels ← 3 times the number of bags of chips

3x - 2 is the number of bags of nachos ← 2 less than bags of pretzels

total snacks bought = x + 3x + 3x - 2 = 7x - 2

6 0

3 years ago

PLEASE HELP!! THANK YOU <3

Natalija [7]

Answer:

what did you need to know :(

3 0

2 years ago

HELP ON THIS PROBLEM!! Solve the following 0deg< x< 360deg: cos x= cos 2x

blsea [12.9K]

Answer:

$x=0^\circ,120^\circ,240^\circ,360^\circ$

Step-by-step explanation:

Use identities to set the equation up as a quadratic

$\cos x=\cos 2x;\:0^\circ \leq x \leq 360^\circ\\\\\cos x=2\cos^2 x-1\\\\0=2\cos^2 x-\cos x-1$

Make the substitution u=cos(x) and solve the quadratic

$0=2u^2-u-1\\\\0=(2u+1)(u-1)$

$\displaystyle 0=2u+1\\\\0=2\cos x+1\\\\-1=2\cos x\\\\-\frac{1}{2}=\cos x\\\\120^\circ,240^\circ=x$

$0=u-1\\\\0=\cos x-1\\\\1=\cos x\\\\0^\circ,360^\circ=x$

Hence, $x=0^\circ,120^\circ,240^\circ,360^\circ$

7 0

1 year ago

If f(x) = -7x + 5x2 + 10, what does f(-2) equal?

aksik [14]

Answer:

f(-2) = 44

Step-by-step explanation:

Hello there! Lets get started solving this function!

For a function, whenever we see f(x) = ... , the function is simply asking the value of the equation at x! So, if replace f(x) with f(-2), we simply substitute x with -2 in the equation! Lets get started!

$f(x) = -7x + 5x^{2} + 10\\f(-2) = -7(-2) + 5(-2)^{2} + 10\\f(-2) = 14 + 20 + 10\\f(-2) = 44\\$

First, we can write the original function. Next, we substitute in -2 for x. Then, we find our final terms. Finally, we are given that f(-2) = 44.

Hope this helps! Remember, math is fun!

7 0

3 years ago

To decrease an amount by 7%, what single multiplier would you use?

Fofino [41]

To decrease something at 100% by 7% is:

100% - 7% = 93%

You multiply the original value by 0.93 to decrease it from it's original value by 7%

7 0

3 years ago