Which expression has a value of 36? 3/7X42. 6/7X21. 3/4X48 10/13X39

This week, we are covering relationships that can be approximated by linear equations. For instance, y = 453x + 3768 represents

lana [24]

Answer:

See explanation below.

Step-by-step explanation:

We assume that the data is given by :

x: 30, 30, 30, 50, 50, 50, 70,70, 70,90,90,90

y: 38, 43, 29, 32, 26, 33, 19, 27, 23, 14, 19, 21.

Where X represent the cost for scholarships in thousands of dollars and y represent the cost of life for an academic semester (The data comes from the web)

We can find the least-squares line appropriate for this data.

For this case we need to calculate the slope with the following formula:

$m=\frac{S_{xy}}{S_{xx}}$

Where:

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}{n}$

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}$

So we can find the sums like this:

$\sum_{i=1}^n x_i = 30+30+30+50+50+50+70+70+70+90+90+90=720$

$\sum_{i=1}^n y_i =38+43+29+32+26+33+19+27+23+14+19+21=324$

$\sum_{i=1}^n x^2_i =30^2+30^2+30^2+50^2+50^2+50^2+70^2+70^2+70^2+90^2+90^2+90^2=49200$

$\sum_{i=1}^n y^2_i =38^2+43^2+29^2+32^2+26^2+33^2+19^2+27^2+23^2+14^2+19^2+21^2=9540$

$\sum_{i=1}^n x_i y_i =30*38+30*43+30*29+50*32+50*26+50*33+70*19+70*27+70*23+90*14+90*19+90*21=17540$

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=49200-\frac{720^2}{12}=6000$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}=17540-\frac{720*324}{12}{12}=-1900$

And the slope would be:

$m=-\frac{1900}{6000}=-0.317$

Nowe we can find the means for x and y like this:

$\bar x= \frac{\sum x_i}{n}=\frac{720}{12}=60$

$\bar y= \frac{\sum y_i}{n}=\frac{324}{12}=27$

And we can find the intercept using this:

$b=\bar y -m \bar x=27-(-0.317*60)=46.02$

So the line would be given by:

$y=-0.317 x +46.02$

We have an inverse linear relationship since the slope is negative between the variables of interest.

8 0

3 years ago

For some math loving friends

shtirl [24]

The first step of finding the percent tip, we must find how much tip she paid:

Tip = $38.61 - $33 = $5.61

To find the percent tip, we must divide the tip amount by the amount she paid before the tip

$5.61 / $33 = 0.17 --> 17%

Thus the percent tip is 17%

Hope that helps!

7 0

2 years ago

4. Is the following definition of perpendicular reversible? If yes, write it as a true biconditional.

artcher [175]

Is the following definition of perpendicular reversible? If yes, write it as a true biconditional.

Two lines that intersect at right angles are perpendicular.

A. The statement is not reversible.

B. Yes; if two lines intersect at right angles, then they are perpendicular.

C. Yes; if two lines are perpendicular, then they intersect at right angles.

D. Yes; two lines intersect at right angles if (and only if) they are perpendicular.

Your Answer would be (D)

Yes; two lines intersect at right angles if (and only if) they are perpendicular.

REF: 2-3 Biconditionals and Definitions

6 0

3 years ago

Read 2 more answers

Can someone help me? Files attached! What answer choices go to what figure? :D

den301095 [7]

Since the center is considered the corner that they both share, here are the answers figure a goes with the first, figure b goes with the last, figure c goes with the second, and figure d goes with the third. Hope this helps.

3 0

3 years ago

Copy the problems onto your paper, mark the given and prove the statements asked. Given: marked Prove: ΔABC ≅ ΔDBC, ΔEHF ≅ ΔGHF

hjlf

The proof is given below. Please go through it.

Step-by-step explanation:

To solve Δ ABC ≅ Δ DBC

From Δ ABC and Δ DBC

AB = BD (given)

AC = CD (given)

BC is common side

By SSS condition Δ ABC ≅ Δ DBC ( proved)

To solve Δ EHF ≅ Δ GHF

Δ EHF and Δ GHF

EH = HG ( given)

∠ EFH = ∠ GFH ( each angle is 90°)

HF is common side

By RHS condition

Δ EHF ≅ Δ GHF

7 0

3 years ago