45% of what number is 27?

An armount of nitrogen undergoes a physical change and increases its volurme, What can be knoW) about this

Allushta [10]

Answer:

d

Step-by-step explanation:

8 0

3 years ago

Help!! 50 points and brainliest!

Viktor [21]

Answer:

Second choice:

$x=2t$

$y=4t^2+4t-3$

Fifth choice:

$x=t+1$

$y=t^2+4t$

Step-by-step explanation:

Let's look at choice 1.

$x=t+1$

$y=t^2+2t$

I'm going to subtract 1 on both sides for the first equation giving me $x-1=t$ . I will replace the $t$ in the second equation with this substitution from equation 1.

$y=(x-1)^2+2(x-1)$

Expand using the distributive property and the identity $(u+v)^2=u^2+2uv+v^2$ :

$y=(x^2-2x+1)+(2x-2)$

$y=x^2+(-2x+2x)+(1-2)$

$y=x^2+0+-1$

$y=x^2$

So this not the desired result.

Let's look at choice 2.

$x=2t$

$y=4t^2+4t-3$

Solve the first equation for $t$ by dividing both sides by 2:

$t=\frac{x}{2}$ .

Let's plug this into equation 2:

$y=4(\frac{x}{2})^2+4(\frac{x}{2})-3$

$y=4(\frac{x^2}{4})+2x-3$

$y=x^2+2x-3$

This is the desired result.

Choice 3:

$x=t-3$

$y=t^2+2t$

Solve the first equation for $t$ by adding 3 on both sides:

$x+3=t$ .

Plug into second equation:

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

Expanding using the distributive property and the earlier identity mentioned to expand the binomial square:

$y=(x^2+6x+9)+(2x+6)$

$y=(x^2)+(6x+2x)+(9+6)$

$y=x^2+8x+15$

Not the desired result.

Choice 4:

$x=t^2$

$y=2t-3$

I'm going to solve the bottom equation for $t$ since I don't want to deal with square roots.

Add 3 on both sides:

$y+3=2t$

Divide both sides by 2:

$\frac{y+3}{2}=t$

Plug into equation 1:

$x=(\frac{y+3}{2})^2$

This is not the desired result because the $y$ variable will be squared now instead of the $x$ variable.

Choice 5:

$x=t+1$

$y=t^2+4t$

Solve the first equation for $t$ by subtracting 1 on both sides:

$x-1=t$ .

Plug into equation 2:

$y=(x-1)^2+4(x-1)$

Distribute and use the binomial square identity used earlier:

$y=(x^2-2x+1)+(4x-4)$

$y=(x^2)+(-2x+4x)+(1-4)$

$y=x^2+2x+-3$

$y=x^2+2x-3$ .

This is the desired result.

3 0

3 years ago

Read 2 more answers

PLS HELP TELL WHETHER X AND Y SHOW DIRECT VARIATION!!!

jarptica [38.1K]

Answer:

Try using this calculator

Step-by-step explanation:

https://www.mathpapa.com/algebra-calculator.html

4 0

3 years ago

Please help! 20 points!!!

KonstantinChe [14]

Answer:

SOLUTION STEPS

6

8

5

+−6

3

1

Multiply 6 and 8 to get 48.

8

48+5

−

3

6×3+1

Add 48 and 5 to get 53.

8

53

−

3

6×3+1

Multiply 6 and 3 to get 18.

8

53

−

3

18+1

Add 18 and 1 to get 19.

8

53

−

3

19

Least common multiple of 8 and 3 is 24. Convert

8

53

and

3

19

to fractions with denominator 24.

24

159

−

24

152

Since

24

159

and

24

152

have the same denominator, subtract them by subtracting their numerators.

24

159−152

Subtract 152 from 159 to get 7.

24

7

Step-by-step explanation:

8 0

2 years ago

Read 2 more answers

Compare partial products and regrouping

Stella [2.4K]

Let us first describe how partial product and regrouping are alike:

Partial Products and Regrouping are alike because both methods are multiplied by one number and if the product of the number has 2 digits it can be carried.

Now let us discuss how they are different:

Partial Products and Regrouping are different because Partial Products are doing multiplication step by step and regrouping is regular multiplication.

Hope it helps.

5 0

3 years ago