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Elena-2011 [213]
3 years ago
11

Please help, thank you

Mathematics
1 answer:
solmaris [256]3 years ago
8 0

Answer:

1.

8x + 6y = 28

9x + 3y = 39

Set to equal y.

8x + 6y = 28

6y = -8x + 28

y = -8/6x + 28/6

y = -4/3x + 14/3

9x + 3y = 39

3y = -9x + 39

y = -9/3x + 39/3

y = -3x + 13

Set equal to each other.

-4/3x + 14/3 = -3x + 13

Combine like terms.

5/3x = 25/3

Multiply by 3/5

x = 5

Plug x in.

y = -3(5) + 13

y = -15 + 13

y = -2

(5, -2)

2.

-2x - 9y = -3

-7x - 9y= -33

Set equal to y.

-2x - 9y = -3

-9y = 2x - 3

y = -2/9x + 3/9

y = -2/9x + 1/3

-7x - 9y= -33

-9y = 7x - 33

y = -7/9x + 33/9

y = -7/9x + 11/3

Set equal to each other

-2/9x + 1/3 = -2/9x + 1/3

0 = 0

infinitely many solutions

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crows are migrating and travel 35 km on a bearing of 047°. Then then fly 15 km of a bearing of 105°. How far , and on wha…
padilas [110]

Answer:

American Crows can be considered partially migratory. That is, some populations migrate, others are resident, and in others only some of the crows migrate. Crows in the southern parts of their range appear to be resident and not migrate. They may make some changes in their use of space at this time, spending more time off the territory to forage and roost. Crows migrate out of the northern most parts of their range. It has been stated that crows migrate out of those areas where the minimum January temperature averages 0 ° F. Certainly crows leave the northern Great Plains in the fall, leaving Saskatchewan and Alberta to winter in the lower Plains states of Nebraska, Kansas, and Oklahoma (Kalmbach, E. R., and S. E. Aldous. 1940. Winter banding of Oklahoma crows. Wilson Bull. 52: 198-206). Crows can be seen crossing the Great Lakes in spring and fall, and these birds undoubtedly are migrating to and from parts of Canada.

Step-by-step explanation:

because  They may make some changes in their use of space at this time, spending more time off the territory to forage and roost. Crows migrate out of the northern most parts of their range. It has been stated that crows migrate out of those areas where the minimum January temperature averages 0 ° F.

3 0
3 years ago
The angle between the top of a building and a point 80 feet away from the base (on level ground) is 70° . To the nearest foot, h
alekssr [168]

Answer: 220 feet tall

Step-by-step explanation:

1. Draw!

2. Use trigonometric ratios to solve for the height (Remember SOH CAH TOA)

3 0
3 years ago
Read 2 more answers
10 POINTS!!! FULL ANSWER WITH FULL STEP BY STEP SOLUTION PLEASE. DO BOTH PARTS OF 1 AND ALL OF 2.
diamong [38]
One A
y = e^x
dy/dx = e^x The f(x) = the differentiated function. Any value that e^x can have, the derivative has the same value. x is contained in all the reals.
One B
y = x*e^x
y' = e^x + xe^x Using the multiplication rule.
You want the slope and the value of the of y to be the same. The slope is y' of the tangent line
xe^x = e^x + xe^x
e^x = 0
This happens only when x is very "small" like x = - 4444444

y = e^x * ln(x) Using the multiplication rule again, we need the slope of the line with is y'
y1 = e^x
y1' = e^x
y2 = ln(x)
y2' = 1/x
y' = e^x*ln(x) + e^x/x So at x = 1 the slope of the line = 
y' = e^1*ln(1) + e^1/1
y' = e*0+e  = e
y = mx + b
y = ex + b
to find b we use y= e^x ln(x)

e^x ln(x) = e*x + b
e^1 ln(1) = e*1 + b
ln(1) = 0
0 = e + b
b = - e

line equation and answer.
y = e*x - e
8 0
3 years ago
Find the absolute extrema for f(x,y)=4-x^2-y^4+1/2y^2 over the closed disk D:x^2+y^2 is less than or equal to 1
algol [13]

Find the critical points of f(x,y):

\dfrac{\partial f}{\partial x}=-2x=0\implies x=0

\dfrac{\partial f}{\partial y}=y-4y^3=y(1-4y^2)=0\implies y=0\text{ or }y=\pm\dfrac12

All three points lie within D, and f takes on values of

\begin{cases}f(0,0)=4\\f\left(0,-\frac12\right)=\frac{65}{16}\\f\left(0,\frac12\right)=\frac{65}{16}\end{cases}

Now check for extrema on the boundary of D. Convert to polar coordinates:

f(x,y)=f(\cos t,\sin t)=g(t)=4-\cos^2-\sin^4t+\dfrac12\sin^2t=3+\dfrac32\sin^2t-\sin^4t

Find the critical points of g(t):

\dfrac{\mathrm dg}{\mathrm dt}=3\sin t\cos t-4\sin^3t\cos t=\sin t\cos t(3-4\sin^2t)=0

\implies\sin t=0\text{ or }\cos t=0\text{ or }\sin t=\pm\dfrac{\sqrt3}2

\implies t=n\pi\text{ or }t=\dfrac{(2n+1)\pi}2\text{ or }\pm\dfrac\pi3+2n\pi

where n is any integer. There are some redundant critical points, so we'll just consider 0\le t< 2\pi, which gives

t=0\text{ or }t=\dfrac\pi3\text{ or }t=\dfrac\pi2\text{ or }t=\pi\text{ or }t=\dfrac{3\pi}2\text{ or }t=\dfrac{5\pi}3

which gives values of

\begin{cases}g(0)=3\\g\left(\frac\pi3\right)=\frac{57}{16}\\g\left(\frac\pi2\right)=\frac72\\g(\pi)=3\\g\left(\frac{3\pi}2\right)=\frac72\\g\left(\frac{5\pi}3\right)=\frac{57}{16}\end{cases}

So altogether, f(x,y) has an absolute maximum of 65/16 at the points (0, -1/2) and (0, 1/2), and an absolute minimum of 3 at (-1, 0).

5 0
3 years ago
Rewrite Log base 4 of 4 = 1
Mkey [24]

Answer:

log_{4}(4)  = 1

4 0
3 years ago
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