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noname [10]
3 years ago
5

A rectangle has length (x+4) cm and width (x-3) cm. Its area is 30 square centimeters. Write a quadratic equation and solve it t

o find the length of the rectangle.
Mathematics
1 answer:
Arturiano [62]3 years ago
6 0

(x+4)(x-3)=30

x^2 +x -12 =30

x^2 +x =42

x^2 +x -42 =0

(i solved it by factorising: _x^2 × -42)

x^2 -6x +7x -42 =0

x(x-6) +7(x-6) 0

(x-6)(x+7)=0

x=6; x=-7

since it's a length, x can't be a negative number, so it must be 6

You might be interested in
The utility industry had 428.5 thousand jobs in 2010 and is expected to decline at an average rate of 3 thousand jobs per year f
e-lub [12.9K]

Answer:

Utility's percent Change from 2010 to 2020 = 7%

Step-by-step explanation:

Jobs available at the utility industry in 2010= 428.5 thousand

Average rate of decline = 3 thousand

Years between 2010 and 2020

Utility's percent Change from 2010 to 2020 = Total change in jobs / jobs in 2010 × 100

Total change in jobs:

There are 10 years between 2010 and 2020

Jobs decline at an average of 3 thousand per year

Total change in jobs= 10 years × 3 thousand

= 30 thousand

Utility's percent Change from 2010 to 2020 = Total change in jobs / jobs in 2010 × 100

= 30 thousand / 428.5 thousand × 100

= 0.07 × 100

= 7%

Utility's percent Change from 2010 to 2020 = 7%

4 0
3 years ago
PLZ HELP WORTH A LOT OF POINTS AND I HAVE 10 MINUTES!!!!
Lina20 [59]

Answer:

The area after 9 years will be 1,234 km^2

Step-by-step explanation:

In this question, we are tasked with calculating what the area of a certain forest that decreases at a certain percentage would be after some years.

To answer this question, we shall be using an exponential approximation.

Now, to use this exponential approximation, we shall be needing a supporting exponential mathematical equation.

This can be written as;

A = I(1-r)^t

where A is the new area we are looking for

I is the initial area which is 1700 according to the question

r is the rate of decrease which is 3.5% = 3.5/100 = 0.035

t is time which is 9 years according to the question

We plug these values and have the following;

A = 1700(1-0.035)^9

A = 1700(0.965)^9

A = 1,233.66

This is 1,234 km^2 to the nearest square kilometer

5 0
3 years ago
3 + b/9 &lt; 4<br>show work please
Gekata [30.6K]

First, before multiplying to cancel the fraction, let's isolate x by subtracting both sides by 3:

b/9 < 1

To cancel out the fraction, we multiply both sides by 9:

x < 9

8 0
3 years ago
Need help stat! 100 POINTS
kirill115 [55]

Answer:

the answer is 67 square inches.

8 0
2 years ago
Read 2 more answers
Write down the gradient of the<br> line with equation y = 5X-8
k0ka [10]

Answer:

Let X be 2

Now,

y = 5*2 - 8

or, y= 10-8

or, y =2

Hope this will help please mark me as <em>brainlest.</em>

6 0
2 years ago
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