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creativ13 [48]
3 years ago
12

3x-10-4

Mathematics
1 answer:
snow_lady [41]3 years ago
8 0

Answer/Step-by-step Explanation:

1. 3x - 10 +4 if x = 3

To evaluate, plug in the value of x in the expression given

3(3) - 10 + 4 = 9 - 10 + 4

= 3

2. \frac{x}{2} + 6x

if x = -12

\frac{(-12)}{2} + 6(-12)

- 6 - 72 = - 78

3. 8(x - y), if x = 2, y = 6

8(2 - 6) = 8(-4) = -32

4. x + xy, if x = 3, y = -2.5

3 + (3)(-2.5) = 3 + (-7.5)

= 3 - 7.5 = - 4.5

5. (2x)² + 6, if x = -2

(2*-2)² + 6 = (-4)² + 6

= 16 + 6 = 22

6. 3x + 4y - 3x, if x = 2, y = 4

3(2) + 4(4) - 3(2) = 6 + 16 - 6

= 16

7. -10x + \frac{4}{x}

If x = -2

-10(-2) + \frac{4}{-2}

20 + (-2) = 20 - 2 = 18

8. 3(8x - 10) + 5x, if x = ½

3(8*½ - 10) + 5(½)

3(4 - 10) + 2.5

3(-6) + 2.5 = -18+2.5 = - 20.5 or 20½

9. x + 8y - (x)², if x = -5, y = ¼

-5 + 8(¼) - (-5)² = -5 + 2 - (25)

= -3 - 25 = -28

10. (8x)² + 6x + 2, if x = -3

(8*-3)² + 6(-3) + 2 = (-24)² - 18 + 2

= 576 - 18 + 2 = 560

11. 2x² + 4y² + xy, if x = ½, y = 2

2(½)² + 4(2)² + (½)(2)

= 2(¼) + 4(4) + 1

= ½ + 16 + 1 = ½ + 17 = 17½

12. 8x + 2y, if x = 1.5, y = -2.2

8(1.5) + 2(-2.2)

12 - 4.4 = 7.6

13. \frac{5}{2}(x - 6) + 4

if x = 8.

\frac{5}{2}(8 - 6) + 4

\frac{5}{2}(2) + 4

= 5 + 4 = 9

14. 3x - 8x² + 7, if x = 4.5

3(4.5) - 8(4.5)² + 7

13.5 - 8(20.25) + 7

13.5 - 162 + 7 = -141.5

15. -2x² + 8y, if x = 3, y = -9

-2(3)² + 8(-9)

-2(9) - 72 = - 18 - 72 = 90

16. (-5x)² - 3x + x, if x = -3.5

(-5*-3.5)² - 3(-3.5) +(-3.5)

(17.5)² + 10.5 - 3.5

306.25 + 10.5 - 3.5 = 313.25

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How to answer this? A farmer had 455 ducks and chickens. He sold 2/5 of the ducks and bought another 104 chickens. As a result,
julia-pushkina [17]

Answer:

(a) 25

(b) $4816

Step-by-step explanation:

Let's say the starting amount of ducks is d, and the starting amount of chickens is c. Since there are only ducks and chickens, we can say that d + c= 455.

Next, the farmer sells 2/5 of the ducks, so we subtract 2/5 of the ducks so that the ending duck amount is d - (2/5)d = (3/5) d

After that, the farmer buys another 104 chickens, so we add 104 chickens to the current amount of chickens to get the ending chicken number as 104+c

Given the ending duck and chicken count, we can say that the ending farm animal count (we can represent this as a) is (3/5)d + 104 + c = a

The number of ducks is 2/3 the total number of animals at the end, so (3/5)d = (2/3)a

Let's list our equations out so it is easier to solve:

d+c = 455

(3/5)d + 104 + c = a

(3/5)d = (2/3)a

We have three equations and need to solve for three variables. One common variable in all three equations is d, so it might help if we put everything in terms of d.

Starting with d+c=455, if we subtract d from both sides, we get c=455-d. We can substitute this in the second equation to get

(3/5)d + 104 + 455 - d = a

-(2/5)d + 559 = a

(3/5)d = (2/3)a

Next, we can substitute for a. If we multiply both sides by 3 and then divide by 2 in (3/5)d = (2/3)a , we get

(9/10)d = a

Substitute that in to the second equation to get

-(2/5)d + 559 = (9/10) d

-(4/10)d + 559 = (9/10) d

add (4/10)d to both sides to isolate the variable and its coefficient

(13/10)d = 559

multiply both sides by (10/13) to isolate the coefficient

d = 430

Therefore, the starting number of ducks is 430 and the starting amount of chickens is 455-430 = 25

For (b), 2/5ths of the ducks are sold, so this is (430) * (2/5) = 172. Each duck is sold for 28 dollars, so this is 172*28=$4816 as the total price

7 0
2 years ago
The sum of two number is 17. their driffrence is 27.write a system of equations that describe this situation. solve to find the
STatiana [176]
A) x + y = 17
B) x - y = 27
Adding both equations:2x = 44
x = 22
y = -5


6 0
3 years ago
Can someone help me? I know I'm doing something wrong but I'm not sure what.
Natasha2012 [34]

Answer:

Step-by-step explanation:

CI = 624 x 1.05 ^3 =722.358 for whole investment   722.36-624 =98.36 for interest only

or for interest only do 624 x .05^3 = 98.36

Standard interest is done like this

year 1 = 624 x 1.05 = 655.20

655.20-624 = 31.20

year 2 = 655.20 + 31.20 = 686.40

year 3 = 686.40 + 31.20 = 717.60

total interest = 717.60-624 = 93.60

So standard interest is the method you have done they may be asking for either compound interest which is the first one or asking for whole investment which means you need to also add 624 at end for Standard interest.

if you need CI interest do the top one.

8 0
2 years ago
What’s the equation for the order pairs (1,-5) and (-2,5)
liq [111]

\bf (\stackrel{x_1}{1}~,~\stackrel{y_1}{-5})\qquad
(\stackrel{x_2}{-2}~,~\stackrel{y_2}{5})
\\\\\\
slope = m\implies
\cfrac{\stackrel{rise}{ y_2- y_1}}{\stackrel{run}{ x_2- x_1}}\implies \cfrac{5-(-5)}{-2-1}\implies \cfrac{5+5}{-2-1}\implies \cfrac{10}{-3}


\bf \begin{array}{|c|ll}
\cline{1-1}
\textit{point-slope form}\\
\cline{1-1}
\\
y-y_1=m(x-x_1)
\\\\
\cline{1-1}
\end{array}\implies y-(-5)=-\cfrac{10}{3}(x-1)\implies y+5=-\cfrac{10}{3}x+\cfrac{10}{3}
\\\\\\
y=-\cfrac{10}{3}x+\cfrac{10}{3}-5\implies y=-\cfrac{10}{3}x-\cfrac{5}{3}

6 0
3 years ago
I figured out that it's A but i need to how many square yards is the combined area of the plot NO LINKS AND NO DOING IT JUST FOR
goblinko [34]

Answer:

I believe both are 80 or 40

Step-by-step explanation:

5 0
3 years ago
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