If the lines and represent three consecutive sides of a rectangle then ab

The correct answer is:

We were given 3 equations we should solve them to find the value of and b and then find ab

Let the rectangle be $ABCD$

The equation of the consecutive sides is given as,

 

$AB\to y=4-3x$ i.e. mAB​=−3

$BC\to ay=x+10$ i.e. mBC​=a1​ and

$CD\to 2y+bx+9=0$ i.e. mCD​=−2b​

 

Now, $AB\parallel CD$ and $BC\perp AB$

∴mAB​=mCD​

 

⇒−3=−2b​

$\Rightarrow b=6$

 

mAB​×mBC​=−1

⇒−3×a1​=−1

 

$\Rightarrow a=3$

$\Rightarrow ab=6\times 3=18$

Hence ab=18
Choice 1 is correct