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2 years ago

Please help me with 7 and 9. First best answer gets brainlist.

Mathematics

2 answers:

Montano1993 [528]2 years ago

7 0

I honestly have no idea

Kitty [74]2 years ago

3 0

I have never done that

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Which is a zero of the quadratic function f(x)=9x^2-54x-19?

Arturiano [62]

A zero, or a solution of the quadratic function is c) x = 6 1/3

Write -54x as a difference
9x^2 + 3x - 57x - 19

Factor 3x out
{ 9x^2 + 3x } - 57x - 19
3x (3x + 1)

Factor -19 out
3x (3x + 1) -19 (3x + 1)

Group the equations
( 3x - 19 ) ( 3x + 1 )

Solve for the zeroes

(3x+1) = 0
-1 -1
3x = -1
3x / 3 = x
-1 / 3 = -1/3
x = - 1/3

(3x - 19) = 0
+19 +19
3x = 19
3x / 3 = x
19 / 3 = 6 1/3
x = 6 1/3

8 0

2 years ago

10 POINTS!!! A truss bridge is shown with two parallel horizontal beams crossed by vertical and slanted beams.

Ugo [173]

Answer:

x=40 °

Step-by-step explanation:

The two horizontal beams are parallel and the slanted beams make a traversal

Hence we use the basic properties of a transverse line making with two parallel lines.

please refer to the image attached to this answer.

The two angles described in the figure makes the alternate interior angles and this these two are congruent . Hence

x= 40°

3 0

3 years ago

Suppose that the functions u and w are defined as follows.

jasenka [17]

Answer(there are assumptions for this answer that you need to confirm and look at):

Assumptions: $u(x)=x^2+3$ and $w(x)=\sqrt{x+2}$

Answer if the operation is multiplication:

If you meant a closed dot which is the symbol for multiplication.

$(u \cdot w)(2)=14$

$(w \cdot u)(2)=14$

Answer if the operation is composition:

If you meant an open dot which is the symbol for composition.

$(u \circ w)(2)=7$

$(w \circ u)(2)=3$

Note: I don't know if you actually meant $w(x)=\sqrt{x+2}$ or if $w(x)=\sqrt{x}+2$ . Please let me know one way or the other.

Step-by-step explanation:

If we assume the functions are:

$u(x)=x^2+3$

$w(x)=\sqrt{x+2}$

$u \cdot w=w \cdot u$ since multiplication is commutative.

$u(2)=2^2+3$

$u(2)=4+3$

$u(2)=7$

$w(2)=\sqrt{2+2}$

$w(2)=\sqrt{4}$

$w(2)=2$

We are asked to find $(u \cdot w)(2)$ and $(w \cdot u)(2)$ .

The order doesn't matter in multiplication.

$(u \cdot w)(2)$

$u(2) \cdot w(2)$

$7 \cdot 2$

$14$

$(w \cdot u)(2)$

$w(2) \cdot u(2)$

$2 \cdot 7$

$14$

Now you might have meant composition which symbolized with an open circle, not a closed one.

$(u \circ w)(2)$

$u(w(2))$

$u(2)$ since $w(2)=2$

$2^2+3$

$4+3$

$7$

$(w \circ u)(2)$

$w(u(2))$

$w(7)$ since $u(2)=7$

$\sqrt{7+2}$

$\sqrt{9}$

$3$

6 0

3 years ago

Simplify the expression.<br> -3(5g + 1) + 8g =<br> Please answer fast! I got 2 minutes!

ehidna [41]

Answer:

-7g - 3

Step-by-step explanation:

1.(0 - 3 • (5g + 1)) + 8g

Pull out like factors :

2.-7g - 3 = -1 • (7g + 3)

and your answer is -7g - 3

8 0

2 years ago

Read 2 more answers

Henrietta did an experiment. She started out with 700 bacteria cells. She found that the growth rate of the bacteria cells was 5

poizon [28]

Answer:

The graph in the attached figure

Step-by-step explanation:

we have a exponential function of the form

$y=a(b^x)$

where

y ---> is the population of bacteria

x ---> the number of hours

a is the initial value or y-intercept

b is the base of the exponential function

r is the rate of change

b=(1+r)

we have

$a=700\ bacteria$

$r=5\%=5/100=0.05$

$b=1+0.05=1.05$

substitute

$y=700(1.05^x)$

For x=20 hours

substitute in the equation and solve for y

$y=700(1.05)^{20} =1,857\ bacteria$

4 0

3 years ago