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3 years ago

The area of a rectangle is 252 cm², and the length is 3 less than 2 times the width. Find the dimensions of the rectangle.

Mathematics

1 answer:

SSSSS [86.1K]3 years ago

3 0

Answer:

21cm, 12cm

Step-by-step explanation:

width=x cm

length=2x-3 cm

area= 252cm²

l*b= 252 cm²

(2x-3)(x)=252

2x²-3x= 252

this is how I did it

we need to find the nearest square of the number (it should be lesser than the area)

that is 225, whose square root is 15.

since there is a coefficient to the x², the value of x would be calculate like this 15- (2+1)= 15-3 = 12

x= 12

we can verify it too,

2*(12)² - 3*12=252

288-36=252

252=252

therefore width is 12 cm and width is 2*12-3= 24-3= 21 cm

verify;

21*12= 252

252=252

hence the dimensions are 12 am (width) and 21 cm(length).

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2 years ago

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Answer:

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Question 1

${ \rm{y = {x}^{2} - 3x + 4 }} \\ { \boxed{ \tt{but \: y = x + 1 \: }}} \\ \\ { \rm{(x + 1) = {x}^{2} - 3x + 4 }} \\ \\ { \rm{ {x}^{2} - 4x + 3 = 0 }} \\ \\ { \rm{(x - 3)(x - 1) = 0}} \\ \\ { \boxed{ \rm{x_{1} = 3 \: \: and \: \: x _{2} = 1}}} \\ \\ { \boxed{ \tt{remember \: y = x + 1}}} \\ \\ { \rm{y _{1} = 4 \: \: and \: \: y _{2} = 2 }}$

Therefore, points of intersection are two

Answer:  (3, 4) and (1, 2)

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Following the steps as in question 1

${ \rm{y = {x}^{2} - 4}} \\ \\{ \rm{2x - 4 = {x}^{2} - 4}} \\ \\ { \rm{ {x}^{2} = 2x }} \\ \\ { \boxed{ \rm{x = 2}}} \\ { \tt{remember : \: y = 2x - 4 }} \\ { \boxed{ \rm{y = 0}}}$

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So in total 40 students were surveyed. I hope the procedure is clear to you.

Step-by-step explanation:

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