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3 years ago

Then work backward to find the cost of 2 dvds

Mathematics

1 answer:

Marizza181 [45]3 years ago

5 0

If the cost of one DVD is $42.70, to find the price of two, multiply 42.70 by two. The price of two DVDs is $85.40.

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At his birthday party Joey got $100 from each of his 2 grandmothers $40 from his dad and $5 from sister, how much did he get? Dr

horsena [70]

He got $245 for his birthday

6 0

3 years ago

Please help me out with this

UNO [17]

Step-by-step explanation:

45+90+x=180

135+x=180

x=180-135

x=45

8 0

3 years ago

Solve the following equations;- x - 9 /√x + 3 =1

fgiga [73]

Answer:

13 , 6.

Step-by-step explanation:

A equation is given to us and we need to find out the value of x . The given equation to us is ,

$\sf\implies \dfrac{ x -9}{\sqrt{x+3}}= 1$

Cross multiply ,

$\sf\implies x - 9 =\sqrt{ x +3}$

Squaring both sides ,

$\sf\implies (x - 9)^2 = x + 3$

Simplify the whole square ,

$\sf\implies x^2+9^2-2.9.x = x +3 \\$

$\sf\implies x^2+81 - 18x = x -3$

Add 3 and subtract x on both sides ,

$\sf\implies x^2 -18x-x +81-3=0$

Simplify ,

$\sf\implies x^2 -19x +78=0$

Split the middle term of the quadratic equation,

$\sf\implies x^2-13x-6x+78=0$

Take out common ,

$\sf\implies x( x -13)-6(x-13)=0$

Take out ( x -13 ) as common ,

$\sf\implies ( x -13)(x-6)=0$

Equate both factors to 0 ,

$\sf\implies \boxed{\pink{\sf x = 13,6}}$

Hence the value of x is 13 or 6 .

7 0

3 years ago

18000lb greater then or less then 9T

Alla [95]

It is equal because every 2000 pounds is 1 ton and 18000lb divided by 2000 equals 9.

5 0

3 years ago

Read 2 more answers

I need to find the derivative. I’m not very good at this so I am answer asap would be sosososo helpful

Bingel [31]

Answer:

See below.

Step-by-step explanation:

First, notice that this is a composition of functions. For instance, let's let $f(x)=\sqrt{x}$ and $g(x)=7x^2+4x+1$ . Then, the given equation is essentially $f(g(x))=\sqrt{7x^2+4x+1}$ . Thus, we can use the chain rule.

Recall the chain rule: $\frac{d}{dx}[f(g(x))]=f'(g(x))\cdot g'(x)$ . So, let's find the derivative of each function:

$f(x)=\sqrt{x}=x^\frac{1}{2}$

We can use the Power Rule here:

$f'(x)=(x^\frac{1}{2})'=\frac{1}{2}(x^{-\frac{1}{2} })=\frac{1}{2\sqrt{x}}$

Now:

$g(x)=7x^2+4x+1$

Again, use the Power Rule and Sum Rule

$g'(x)=(7x^2+4x+1)'=(7x^2)'+(4x)'+(1)'=14x+4$

Now, we can put them together:

$y'=f'(g(x))\cdot g'(x)=\frac{1}{2\sqrt{g(x)}} \cdot (14x+4)$

$y'=\frac{14x+4}{2\sqrt{7x^2+4x+1} } =\frac{7x+2}{\sqrt{7x^2+4x+1} }$

5 0

3 years ago