If 2x – 3y + 1, x + y – 1 and 3x – y – 9 denote the three sides of an equilateral triangle.
Find its perimeter.
21 cm
Since, all sides are equal∴2x−3y+1=x+y−1x−4y=−2...............(i)Also,x+y−1=3x−y−9⇒x−3x+y+y=−8⇒−2x+2y=−8⇒x−y=4..................(ii)On subtracting (ii) from (i), we get−3y=−6⇒y=2On substituting y=2, in (ii), we havex−2=4⇒x=6 Therefore side=2x−3y+1=2×6−3×2+1=6+1=7 cmand perimeter=3×side=21 cm.