SOLUTION: A certain number is added to 20, and the same number is also added to 21; the product of the two sums is 930. What is the number ?
Algebra.Com
Question 203255: A certain number is added to 20, and the same number is also added to 21; the product of the two sums is 930. What is the number ?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
A certain number is added to 20,
That's (x+20)
:
and the same number is also added to 21;
That's (x+21)
:
the product of the two sums is 930.
(x+20)*(x+21) = 390
FOIL
x^2 + 41x + 420 = 930
:
x^2 + 41x + 420 - 930 = 0
:
x^2 + 41x - 510 = 0
Factor
(x+51)(x-10) = 0
Two solutions
x = -51
x = +10
:
You can check and see that both solutions are valid
RELATED QUESTIONS
What is the number that must be added to 100 and to 20(the same number to each) so that... (answered by Alan3354)
If two thirds of a certain number is added to one number half of the number, the result... (answered by Alan3354)
When 5 is added to a certain number, and also taken from that number, the product of the... (answered by Alan3354,josgarithmetic)
When 3 times a certain number N is added to 6, the sum is 20 more than the original... (answered by kdr)
If four is added to twice a number and the sum is multiplied by three, the result is the... (answered by edjones)
If 4 is added to twice a number and this sum is multiplied by two, the result is... (answered by MathTherapy)
If 4 is added to twice a number and this sum is multiplied by 4 the result is the same... (answered by Edwin McCravy)
A number added to the product of 20 and the reciprocal of the number is 9. Find the... (answered by stanbon)
When 3 times a certain number n is added to 6, the sum is 20 more than the original... (answered by robertb)