Question

the perimeter of a rectangle is 30cm and its area is 50 cm^2.find the length of the rectangle.

Answer 1

Perimeter is 30cm
Area= 50cm^2
Now,form simultaneous equation;
2l+2w=30
l*w=50
l=50/w
substitute into first equation:
2(50/w)+2w=30
100/w+2w=30
find LCM of w and 1; that is w
Therefore; (100 + 2w square)/w = 30
Multiply by w both sides to cancel(to get rid of) the denominator
w * 100+ 2w square/w = 30 * w
Therefore; 100+2w square = 30w
2w^2 - 30w + 100 = 0
Now this becomes a quadratic equation;
a= 2 b=-30 c= 100
now you substitute the values of a b and c in the formula.