Answers

2014-10-19T01:00:51+08:00
Let x = length of base
altitude = x+7
area of triangle = 1/2 * x(x+7) =30
                         1/2( x²+7x)  = 30
                           x²+7x = 60          / multiply both sides by 2
                           x²+7x-60= 0
                           (x+12)(x-5) =0
                           x= -12 or x= 5
thus
the length of base =  5ft  & the attitude = 5+7 = 12ft

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