if the area of a rectangle is 243m² and the length is 4b-9 (b-base)
find it's perimeter (pls. with steps)
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l=4b-9
area=243
l×b=243 (4b-9)b=243
4b²-9b-243=0
4b²-36b+27b-243=0
4b(b-9)+27(b-9)=0
(b-9)(4b+27)=0
b=9,-27/4
base can't be negative so b=9 and
l=4×9-9=27
so perimeter=2*(l+b)=2*(9+27) =70
area=243
l×b=243 (4b-9)b=243
4b²-9b-243=0
4b²-36b+27b-243=0
4b(b-9)+27(b-9)=0
(b-9)(4b+27)=0
b=9,-27/4
base can't be negative so b=9 and
l=4×9-9=27
so perimeter=2*(l+b)=2*(9+27) =70
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