Question

Which expression is equivalent to x^2 - 4x - 45

Answer 1

To x^2 - 4x - 45, find equivalent expression

Find 2 numbers m,n such that

m +n = -4

m - n = √ (-4)^2 - 4•(-45) = √(16 +180) = √196

m- n = √196 = 14

Now solve the system 2x2, add both equations

m + n + m -n = -4 + 14 = 10

then 2m = 10 , So then m= 10/2= 5

Now rest to find n

m + n = -4 then n = -4- m = -4-5= -9

n= -9

Now write equation

(x+m)•(x+n) = (x + 5) •( x - 9)

this is an equivalent expression