Please help! 21 is 30% of what number? Enter your answer in the box.
2 answers:
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Answer:
Step-by-step explanation:
The question is not correct (particularly the expression for the area)
A=2lh+2wh
Now we are expected to solve for l, that is we are going to make l subject of the formula, we have
let us take the second term on the RHS to the LHS
we can now divide both sides by 2h we have
hence the expression for the length is
= > x² + 7x + 12 = 12
= > x² + ( 4 + 3 )x + 12 = 12
= > x² + 4x + 3x + 12 = 12
= > x( x + 4 ) + 3( x + 4 ) = 12
= > ( x + 4 ) ( x + 3 ) = 12
Percy did correct till this step. But by doing like this, Percy can't get the values of the variable x.
Percy should follow the following steps :
= > x² + 7x + 12 = 12
Add -12 on both sides,
= > x² + 7x + 12 - 12 = 12 - 12
= > x² + 7x = 0
= > x( x + 7 ) = 0
= > ( x = 0 ) or ( x + 7 = 0 )
= > ( x = 0 ) or ( x = - 7 )
Hence, required value(s) of x is 0 or -7
= > x² + ( 4 + 3 )x + 12 = 12
= > x² + 4x + 3x + 12 = 12
= > x( x + 4 ) + 3( x + 4 ) = 12
= > ( x + 4 ) ( x + 3 ) = 12
Percy did correct till this step. But by doing like this, Percy can't get the values of the variable x.
Percy should follow the following steps :
= > x² + 7x + 12 = 12
Add -12 on both sides,
= > x² + 7x + 12 - 12 = 12 - 12
= > x² + 7x = 0
= > x( x + 7 ) = 0
= > ( x = 0 ) or ( x + 7 = 0 )
= > ( x = 0 ) or ( x = - 7 )
Hence, required value(s) of x is 0 or -7