To find the area of a triangle, use the formula that is A= 1/2(base x height)
L=7+w
P=(12x+14)=2(6x+7)
l+w= P/2 = 2(6x+7)/2= 6x+7
l+w=6x+7
2l = 6x+7
l = (6x+7)/2
l=7+w
-> w= l-7
= [(6x+7)/2] -7
= (6x+7-14)/2
= (6x-7)/2
3x - 5 + 2x = 15+ 4x - 5
5x - 5 = 10 + 4x
5x - 5 + 5 = 10 +5 +4x
5x = 4X + 15
5x - 4x = 4x - 4x + 15
x = 15