We will use the substitution:
t = x² ;
t² + 21 x - 100 = 0
t² + 25 t - 4 t - 100 = 0
t ( t + 25 ) - 4 ( t + 25 ) = 0
( t + 25 ) ( t - 4 ) = 0
t 1 = - 25, t 2 = 4
x = √t
Answer:
The roots are:
x 1 = 5 i
x 2 = - 5 i
x 3 = - 2
x 4 = 2
1/4
because not a lot of students have both gender as siblings!
let's firstly convert the mixed fractions to improper fractions and then add them up, bearing in mind that the LCD from 12 and 6 will just be 12.
Answer:
(x - 3)(x - 7)
Step-by-step explanation:
Please use the symbol " ^ " for exponentiation: x^2 - 10x + 21.
Note that 3*7 = 21 and that 3+7 = 10. These are the clues we need to factor x^2 - 10x + 21. If we factor by grouping, we get:
x^2 - 10x + 21 = (x - 3)(x - 7). Note how -3x and -7x add up to -10 x (as they should), and that -3 times -7 is +21 (as required).