ME ajudem porfavor não aguento mais, tá muito dificil

Mathematics

1 answer:

mihalych1998 [28]3 years ago

8 0

Answer:

say it in English plZz

I can't understand Spanish or whatever ur saying sorry

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1.) Use the quadratic formula to solve the equation. If necessary, round to the nearest hundredth .x squared minus 21 x equals n

Andrew [12]

Part 1
We are given $x^2-21x=-4x$ . This can be rewritten as $x^2-18x=0$ .
Therefore, a=1, b=-18, c=0.
Using the quadratic formula
$x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}=\frac{-\left(-18\right)\pm \sqrt{\left(-18\right)^2-4\left(1\right)\left(0\right)}}{2\left(1\right)}$
$x=\frac{18\pm 18}{2}$

The values of x are
$x_1=\frac{18-18}{2}=0$
$x_2=\frac{18+18}{2}=18$

Part 2
Since the values of y change drastically for every equal interval of x, the function cannot be linear. Therefore, the kind of function that best suits the given pairs is a quadratic function.

Part 3.
The first equation is $y=x^2+2$ .
The second equation is $y=3x+20$ .

We have
$x^2+2=3x+20$
$x^2-3x-18=0$
Factoring, we have
$\left(x-6\right)\left(x+3\right)=0$
Equating both factors to zero.
$x_1-6=0\rightarrow x_1=6$
$x_2+3=0\rightarrow x_2=-3$

When the value of x is 6, the value of y is
$y=3\left(6\right)+20=38$

When the value of x is -3, the value of y is
$y=3\left(-3\right)+20=11$

Therefore, the solutions are (6,38) or (-3,11)

7 0

3 years ago

soymeal is 14 percent protein cornmeal is 7 percent protein how many pounds of each should be mixed together in order to get 280

erma4kov [3.2K]

Let the weight of soymeal be s, and let the weight of cornmeal be c.
You need a total of 280 lb, so that gives us one equation.

s + c = 280

Now we use the protein to write another equation.
The protein in s lb of soymeal is 0.14s.
The protein in c lb of cornmeal is 0.07c.
The protein in 280 lb of 0.09% protein mix is 0.09(280).
This gives us a second equation.

0.14s + 0.07c = 0.09(280)

Now we solve the two equations as a system of equations.

s + c = 280
0.14s + 0.07c = 0.09(280)

Solve the first equation for s and plug in tot eh second equation.

s = 280 - c

0.14(280 - c) + 0.07c = 25.2

39.2 - 0.14c + 0.07c = 25.2

-0.07c = -14

c = 200

Now we substitute c = 200 in the first equation to find s.

s + 200 = 280

s = 80

Answer: 200 lb of soymeal and 80 lb of cornmeal

6 0

3 years ago

The standard form of the equation of a parabola is y = 7x2 + 14x + 4. What is the vertex form of the equation?

Drupady [299]

The vertex of <span>y = 7x2 + 14x + 4</span> is at (-1,-3) (see attachment)