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2 years ago

Find and explain wallys mistake!!

Mathematics

1 answer:

Marysya12 [62]2 years ago

5 0

Answer:

What Wally did wrong is that it is supposed to be (4a-5)(a-4)

In order to get -21 a. He was supposed to use negative 5 and 4 to get to negative 21

If he used (4a+5)(a+5)

The answer will be positive 21 and that's not what the problem is asking

Step-by-step explanation:

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A gas company charges $0.4544 for each therm used. A home used 39.3 therms in a month. How much will the gas company charge that

podryga [215]

Answer:

$17.85792

Step-by-step explanation:

$0.4544 x 39.3 = $17.85792

7 0

2 years ago

Maureen went on a 3 day, 50 mile biking trip. The first day she biked 14.3 miles. The second day she biked 21.1 miles. How many

Mila [183]

Answer:

Step-by-step explanation:

14.3 + 21.1 + x = 50

35.4 + x = 50

x = 50 - 35.4

x = 14.6 <=== she biked 14.6 miles on the 3rd day

7 0

3 years ago

Read 2 more answers

Simplify u^2+3u/u^2-9<br> A.u/u-3, =/ -3, and u=/3<br> B. u/u-3, u=/-3

VashaNatasha [74]

  The correct answer is: Answer choice: [A]:
__________________________________________________________
→  " $\frac{u}{u-3}$ " ; " { u $\neq$ ± 3 } " ;

  →  or, write as: " u / (u − 3) " ;  {" u ≠ 3 "}  AND: {" u ≠ -3 "} ;
__________________________________________________________
Explanation:
__________________________________________________________
We are asked to simplify:

   $\frac{(u^2+3u)}{(u^2-9)}$ ;

Note that the "numerator" —which is: "(u² + 3u)" — can be factored into:
  → " u(u + 3) " ;

And that the "denominator" —which is: "(u² − 9)" — can be factored into:
  → "(u − 3) (u + 3)" ;
___________________________________________________________
Let us rewrite as:
___________________________________________________________

→ $\frac{u(u+3)}{(u-3)(u+3)}$ ;

___________________________________________________________

→ We can simplify by "canceling out" BOTH the "(u + 3)" values; in BOTH the "numerator" AND the "denominator" ;  since:

" $\frac{(u+3)}{(u+3)} = 1$ " ;

→ And we have:
_________________________________________________________

→  " $\frac{u}{u-3}$ " ; that is: " u / (u − 3) " ; { u $\neq 3$ } .
and: { u $\neq-3$ } .

→ which is:  "Answer choice: [A] " .
_________________________________________________________

NOTE:  The "denominator" cannot equal "0" ; since one cannot "divide by "0" ;

and if the denominator is "(u − 3)" ; the denominator equals "0" when "u = -3" ; as such:

"u $\neq$ 3" ;

→ Note: To solve: "u + 3 = 0" ;

Subtract "3" from each side of the equation;

→ " u + 3 − 3 = 0 − 3 " ;

→ u = -3 (when the "denominator" equals "0") ;

→ As such: " u $\neq$ -3 " ;

Furthermore, consider the initial (unsimplified) given expression:

→   $\frac{(u^2+3u)}{(u^2-9)}$ ;

Note:  The denominator is: "(u²  − 9)" .

The "denominator" cannot be "0" ; because one cannot "divide" by "0" ;

As such, solve for values of "u" when the "denominator" equals "0" ; that is:
_______________________________________________________

→ " u² − 9 = 0 " ;

→ Add "9" to each side of the equation ;

→ u² − 9 + 9 = 0 + 9 ;

→ u² = 9 ;

Take the square root of each side of the equation;
to isolate "u" on one side of the equation; & to solve for ALL VALUES of "u" ;

→ √(u²) = √9 ;

→ | u | = 3 ;

→ " u = 3" ; AND; "u = -3 " ;

We already have: "u = -3" (a value at which the "denominator equals "0") ;

We now have "u = 3" ; as a value at which the "denominator equals "0");

→ As such: " u $\neq 3$ " ; "u $\neq$ -3 " ;

or, write as: " { u $\neq$ ± 3 } " .

_________________________________________________________

6 0

3 years ago

Caleb bought groceries and paid \$1.60$1.60dollar sign, 1, point, 60 in sales tax. The sales tax rate is 2.5\%2.5%2, point, 5, p

saveliy_v [14]

Answer:

Price of Caleb's groceries before tax = $64

Step-by-step explanation:

Let the price of groceries before tax be =$ $x$

Sales tax charged = $1.60

Sales tax rate =2.5%

Sales tax charged in terms of $x$ will be = 2.5% of the Original price of grocery = $2.5\% of x = 0.025\times x=0.025x$

So, we have,

$0.025x=1.60$

Dividing both sides by $0.025$

$\frac{0.025x}{0.025}=\frac{1.60}{0.025}$

∴ $x=64$

∴ Price of Caleb's groceries before tax = $64

5 0

3 years ago

An up-and-coming artist has 85 followers on Twitter and this number doubles every week. In what week will the artist first reach

Alik [6]

Answer:

5.8 , which approximately is 6 weeks.

Step-by-step explanation:

the first method is the short one since u just have to double the 85 then divide to 1000.

1000 ÷ ( 85 × 2)

1000 ÷ 170 = 5.882,,,,,. round off to whole number to get 6.

the second method is the addition method.

we start by 85 then keep doubling 85 for every week........inshort.......we add 170 to each weeks number to get the number of followers for the following week.

85 ⇒ 170 ⇒ 340 ⇒ 510 ⇒ 680 ⇒ 850 ⇒ 1020.

1st 2nd 3rd 4th 5th 6th week.

u notice that we add (85×2), 170, to get the following week's number of followers..

in 5 weeks..... the number of followers is yet to get to 1000.

when u divide, u get 5.8.....,and it is not logic to say 5.8823....weeks

since she reaches 1000 followers in the 6th week.......though there is an addition,,,, it is the most appropriate answer.

3 0

3 years ago