Reinaldo A. answered 07/09/20
Engineer and Rice Graduate
You are looking for three numbers x, y, and z that fit the equation x2+2(y+z) = 51.
However, we know the numbers are consecutive integers, so we can say:
- y = x+1
- z = x+2
This reduces our equation to be a one-variable equation:
- x2+2(x+1+x+2) = 51
- x2+2(2x+3) = 51
- x2+4x+6 = 51
- x2+4x-45 = 0
From here, we need to factor the quadratic.
- We know that the constants must be two integers that multiply into -45, and add up to 4.
- If you know your multiplication table well, you'll know 9 and 5 multiply to 45.
- We want the product to be negative, so one of the constants needs to be negative and the other positive.
- Since they add up to positive 4, we know the greater of the two (9) should be positive. This gives us:
- (x+9)(x-5) = 0
So our two solutions are x = -9 and x = 5. Plug these in to the original equation and we get:
- y = -8 or 6
- z = -7 or 7
- x = -9 gives us (-9)2+2(-8-7) = 81+2(-15) = 81-30 = 51
- x = 5 gives us 52+2(6+7) = 25+2(13) = 25+26 = 51
So, your answer could be (-9,-8,-7) or (5,6,7)