Kevin B. answered • 04/02/19
Tutor
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(63)
Math and Microsoft Office Tutoring
While this could be solved with two equations and factoring it is far easier to use trial and error:
Find two numbers whose product is 9:
1st try
3 x 3 =9 3+3= 6 so that doesn't work since the numbers don't total 10
2nd try
1 x 9 =9 1+9 =10 That combination of numbers works!
So the answer is: 1 and 9
Kevin B.
Assuming the question is "Two numbers whose product is -9 and sum is 10" Let x = the first number and y = 10 - x be the second number. The we can say the product xy=-9 is the same as x (10-x) = -9 That simplifies to 10x - x^2 = -9 which is the same as x^2 - 10x -9 = 0 x = 5 +/- sqrt(34) If x = 5 + sqrt (34) then y = 10 - (5 + sqrt(34)) = 5 - sqrt(34) xy = (5+sqrt(34) )(5-sqrt(34)) = 25 +5sqrt(34) -5sqrt(34) -34 That simplifies to 25 -34 = -9 That works, but we need to try x = 5 - sqrt(34) as well If x = 5 - sqrt(34), then y = 10 - (5 - sqrt(34) ) = 5 + sqrt(34) The xy = (5 - sqrt(34) )(5 +sqrt(34) ) = 25 - 5sqrt(34) + 5sqrt(34) -34 That simplifies to 25 -34 = -9 so that works as well, but as it turns out it is just the opposite of the first solution we checked. One number is 5 + sqrt(34) and the other is 5 - sqrt(34) The sum is 10 and the product is -9. I hope that helps!
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11/21/22
OneWho D.
What if it is whose factor is -9 and whose sum is 10?11/20/22