If the area of the parallelogram with a and b as two adjacent sides is 15 sq. units, then the area of the parallelogram having 3 a + b and a +3 b as two adjacent sides, in square units, is

Step-by-step solution

Area of parallelogram =| a b |=15 [given] Area of second parallelogram =|(3 a + b ) ( a +3 b )| aligned & =|3 a a +9 a b + b a +3 b b | & =|0+9 a b - a b +0| & =|8 a b |=8| a b |=8 15=120 aligned