Question

the product of a girl age five years ago and 8 years from now is 30.find her present age.​

Answer 1

Let her present age be x

(x-5)(x+8)=30

x^2+8x-5x-40=30

x^2+3x-70=0

x^2+10x-7x-70=0

x(x+10)-7(x+10)=0

(x-7)(x+10)=0

x=7. accept x=-10reject

so her present age is 7 years answer

plz mark it as brainliast answer

Answer 2

Present age of girl is 7 years

Explanation:

Let the present age of girl be ' x ' years

Age of girl 5 years ago = ( x - 5 ) years

Age of girl 8 years from now = ( x + 8 ) years

Product = 30

=> ( x - 5 )( x + 8 ) = 30

=> x(x + 8) - 5( x + 8 ) = 30

=> x² + 8x - 5x - 40 = 30

=> x² + 3x - 40 = 30

=> x² + 3x - 40 - 30 = 0

=> x² + 3x - 70= 0

=> x² + 10x - 7x - 70 = 0

=> x(x + 10) - 7(x + 10) = 0

=> (x + 10)(x - 7) = 0

=> x + 10 = 0 or x - 7 = 0

=> x = - 10 or x = 7

But x = - 7 is neglected since ages cannot be negative

=> x = 7

Therefore the present age of girl is 7 years