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3 years ago

(9x2 + 8x) – (2x2 + 3x)

Mathematics

2 answers:

laila [671]3 years ago

8 0

The answer is 19x.
Your welcome for the answer. :)

Arte-miy333 [17]3 years ago

7 0

Answer: 14+5x

Step-by-step explanation:

(18+8x) - (4+3x)

18+8x-4-3x

14+5x

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the length of a rectangle is five feet less than its width. If the area of the rectangle is 84 square feet, find its dimensions

KIM [24]

Let
x---------> the length of the rectangle
y--------> the width of the rectangle

we know that
A=84 ft²
[area of rectangle]=x*y-----> 84=x*y-----> equation 1
x=y-5------> equation 2
substitute 2 in 1
84=[y-5]*y-----> 84=y²-5y---------> y²-5y-84=0

using a graph tool-----> to resolve the second order equation
see the attached figure

the solution is
y=12
x=y-5-----> x=12-5-----> x=7

the answer is
the length of the rectangle is 7 ft
the width of the rectangle is 12 ft

6 0

3 years ago

Two planes left simultaneously from the same airport and headed in the same direction towards another airport 3600 km away. The

ExtremeBDS [4]

Answer:

800 kph
600 kph

Step-by-step explanation:

Equation

Let s represent the speed of the faster plane. Then its travel time is ...

time = distance/speed = 3600/s

travel time for the slower plane is ...

time = distance/speed = 3600/(s -200)

The difference in these times is 1.5 hours, so we have ...

3600/(s -200) -3600/s = 1.5

Solution

Multiplying by (2/3)s(s -200), we get ...

2400(s) -2400(s -200) = s(s -200)

s^2 -200s -480000 = 0 . . . . . . . . . . rewrite in standard form

(s -800)(s +600) = 0 . . . . . . . . . . . . . factor

The positive value of s that makes a factor zero is s = 800.

Conclusion

The speed of the faster plane was 800 km/h; of the slower plane, 600 km/h.

_____

Check

The travel time for the faster plane was 3600/800 = 4.5 hours. For the slower plane, 3600/600 = 6 hours, a difference of 1.5 hours.

6 0

2 years ago

2) 3x + 4y = 8 2x+y=42 a) (30, -19) b) (31, -20) c) (32,-22) What is the answer

kirza4 [7]

Answer:

Step-by-step explanation:

We can solve simultaneous equations using substitution method, elimination method or graphical method. But for this purpose, we will be using the elimination method.

3x+4y=8 Equation 1

2x+y=42 Equation 2

Multiply Equation 1 by 2 and equation 2 by 3, so as to get the same coefficient for x

2(3x+4y=8)= 6x+8y=16 Equation 3

3(2x+y=42)= 6x+3y=126 Equation 4

Subtract equation 4 from 3, to eliminate x

6x-6x=0

8y-3y= 5y

16-126= -110

We now have 5y=-110

Divide both sides by 5,

y= -110/5

= -22

Substituting for y in equation 2

2x+(-22)= 42

2x= 42+22

2x=64

x= 64/2

= 32

(x, y)

(32, -22)

7 0

3 years ago

GUYS PLS HELP ME, its math and I'm really stuck

DiKsa [7]

Answer:

B. 1/2

Step-by-step explanation:

You can see that when two weeks that pass, the plant grows one inch. This rate can be written as 1 inch : 2 weeks. But, we need to find the unit rate. To find the unit rate, or how many inches the plant grows per week, we divide both by 2.

1/2 inch : 1 week

1/2

I Hope That This Helps! :)

7 0

2 years ago

What is 58.65 with a 15% tip?

11111nata11111 [884]

X/58.65 = 15/100

(58.65*15)/100 = tip

6 0

2 years ago