Can anyone help me????

1)Sheyna drive to the lake and back. It took two hours less time to get there than it did to get back. The average speed on the

ipn [44]

Answer:

8 hours

Step-by-step explanation:

Given:

Sheyna drives to the lake with average speed of 60 mph and

$v_1 = 60\ mph$

Sheyna drives back from the lake with average speed of 36 mph

$v_2 = 36\ mph$

It took 2 hours less time to get there than it did to get back.

Let $t_1$ be the time taken to drive to lake.

Let $t_2$ be the time taken to drive back from lake.

$t_2-t_1 = 2$ hrs ..... (1)

To find:

Total time taken = ?

$t_1+t_2 = ?$

Solution:

Let D be the distance to lake.

Formula for time is given as:

$Time =\dfrac{Distance}{Speed }$

$t_1 = \dfrac{D}{60}\ hrs$

$t_2 = \dfrac{D}{36}\ hrs$

Putting in equation (1):

$\dfrac{D}{36}-\dfrac{D}{60} = 2\\\Rightarrow \dfrac{5D-3D}{180} = 2\\\Rightarrow \dfrac{2D}{180} = 2\\\Rightarrow D = 180\ miles$

So,

$t_1 = \dfrac{180}{60}\ hrs = 3 \ hrs$

$t_2 = \dfrac{180}{36}\ hrs = 5\ hrs$

So, the answer is:

$t_1+t_2 = \bold{8\ hrs}$

8 0

3 years ago

HELP ASAP!!!

Umnica [9.8K]

Rearrange:

Rearrange the equation by subtracting what is to the right of the equal sign from both sides of the equation :

(a)/(a^2-16)+(2/(a-4))-(2/(a+4))=0

Simplify ————— a + 4 Equation at the end of step 1 : a 2 2 (—————————+—————)-——— = 0 ((a2)-16) (a-4) a+4 Step 2 : 2 Simplify ————— a - 4 Equation at the end of step 2 : a 2 2 (—————————+———)-——— = 0 ((a2)-16) a-4 a+4 Step 3 : a Simplify ——————— a2 - 16 Trying to factor as a Difference of Squares :

3.1 Factoring: a2 - 16

Theory : A difference of two perfect squares, A2 - B2 can be factored into (A+B) • (A-B)

Proof : (A+B) • (A-B) =
 A2 - AB + BA - B2 =
 A2 - AB + AB - B2 =
 A2 - B2

Note : AB = BA is the commutative property of multiplication.

Note : - AB + AB equals zero and is therefore eliminated from the expression.

Check : 16 is the square of 4
Check : a2 is the square of a1 

Factorization is : (a + 4) • (a - 4)

Equation at the end of step 3 : a 2 2 (————————————————— + —————) - ————— = 0 (a + 4) • (a - 4) a - 4 a + 4 Step 4 :Calculating the Least Common Multiple :

4.1 Find the Least Common Multiple

 The left denominator is : (a+4) • (a-4)

 The right denominator is : a-4

Number of times each Algebraic Factor
 appears in the factorization of: Algebraic
 Factor Left
Denominator Right
Denominator L.C.M = Max
{Left,Right} a+4 101 a-4 111

Least Common Multiple:
(a+4) • (a-4)

Calculating Multipliers :

4.2 Calculate multipliers for the two fractions

 Denote the Least Common Multiple by L.C.M
 Denote the Left Multiplier by Left_M
 Denote the Right Multiplier by Right_M
 Denote the Left Deniminator by L_Deno
 Denote the Right Multiplier by R_Deno

 Left_M = L.C.M / L_Deno = 1

 Right_M = L.C.M / R_Deno = a+4

Making Equivalent Fractions :

4.3 Rewrite the two fractions into equivalent fractions

Two fractions are called equivalent if they have the same numeric value.

For example : 1/2 and 2/4 are equivalent, y/(y+1)2 and (y2+y)/(y+1)3 are equivalent as well.

To calculate equivalent fraction , multiply the Numerator of each fraction, by its respective Multiplier.

L. Mult. • L. Num. a —————————————————— = ————————————— L.C.M (a+4) • (a-4) R. Mult. • R. Num. 2 • (a+4) —————————————————— = ————————————— L.C.M (a+4) • (a-4) Adding fractions that have a common denominator :

4.4 Adding up the two equivalent fractions
Add the two equivalent fractions which now have a common denominator

Combine the numerators together, put the sum or difference over the common denominator then reduce to lowest terms if possible:

a + 2 • (a+4) 3a + 8 ————————————— = ————————————————— (a+4) • (a-4) (a + 4) • (a - 4) Equation at the end of step 4 : (3a + 8) 2 ————————————————— - ————— = 0 (a + 4) • (a - 4) a + 4 Step 5 :Calculating the Least Common Multiple :

5.1 Find the Least Common Multiple

 The left denominator is : (a+4) • (a-4)

 The right denominator is : a+4

Number of times each Algebraic Factor
 appears in the factorization of: Algebraic
 Factor Left
Denominator Right
Denominator L.C.M = Max
{Left,Right} a+4 111 a-4 101

Least Common Multiple:
(a+4) • (a-4)

Calculating Multipliers :

5.2 Calculate multipliers for the two fractions

 Denote the Least Common Multiple by L.C.M
 Denote the Left Multiplier by Left_M
 Denote the Right Multiplier by Right_M
 Denote the Left Deniminator by L_Deno
 Denote the Right Multiplier by R_Deno

 Left_M = L.C.M / L_Deno = 1

 Right_M = L.C.M / R_Deno = a-4

Making Equivalent Fractions :

5.3 Rewrite the two fractions into equivalent fractions

L. Mult. • L. Num. (3a+8) —————————————————— = ————————————— L.C.M (a+4) • (a-4) R. Mult. • R. Num. 2 • (a-4) —————————————————— = ————————————— L.C.M (a+4) • (a-4) Adding fractions that have a common denominator :

5.4 Adding up the two equivalent fractions

(3a+8) - (2 • (a-4)) a + 16 ———————————————————— = ————————————————— (a+4) • (a-4) (a + 4) • (a - 4) Equation at the end of step 5 : a + 16 ————————————————— = 0 (a + 4) • (a - 4) Step 6 :When a fraction equals zero : 6.1 When a fraction equals zero ...

Where a fraction equals zero, its numerator, the part which is above the fraction line, must equal zero.

Now,to get rid of the denominator, Tiger multiplys both sides of the equation by the denominator.

Here's how:

a+16 ——————————— • (a+4)•(a-4) = 0 • (a+4)•(a-4) (a+4)•(a-4)

Now, on the left hand side, the (a+4) • (a-4) cancels out the denominator, while, on the right hand side, zero times anything is still zero.

The equation now takes the shape :
a+16 = 0

Solving a Single Variable Equation :

6.2 Solve : a+16 = 0

Subtract 16 from both sides of the equation :
 a = -16

One solution was found :

a = -16

4 0

3 years ago

How do i solve this equation

Gre4nikov [31]

X < -16 is the solution
Hope this helped

6 0

3 years ago

5. At a picture frame shop you order a $52 picture frame. You have a $40 gift certificate and a

svetoff [14.1K]

Do the 11% off first.

11% of 52$ is 46.38$, then you take $40 off and your total is only $6.38

if you do -40$ first then you have $12 left and 11% off that is $10.68.

3 0

3 years ago

Express 72×12 in the exponential form

kobusy [5.1K]

72*12 = 2*2*2*2*2*3*3*3 = 2^5*3^3

3 0

3 years ago