The area of a rectangle is 20 cm^2. The height is 4 cm longer than thrice the width.
Answers
Answered by
4
Step-by-step explanation:
the lenght is 3x+4
the height is x
the area is
x *3x+4
3x2+4x =20
3x^2 +4x-20=0
by quadratic equations
3x^2 + 10x - 6x -20=0
x( 3x+10) - 2(3x+10)=0
x-2=0
x is 2
OR
3x+10=0
x= -10/3 not possible as side never negative
hence breadth is 2 and length is 10cm
Answered by
3
The height is 4 cm longer than thrice the width.
Take the width x.
Then, 4=height-3*width
So, height=3*width+4
Height is 3x+4.
Now we write the quadratic equation x(3x+4)=20
3x²+4x-20=0
By splitting the middle term
3x²-6x+10x-20=0
3x(x-2)+10(x-2)=0
(3x+10)(x-2)=0 ∴x=2 since x>0.
Width : 2 cm, Height : 10 cm
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