00:01
Given expression is x squared plus 9x plus 20.
00:09
To find out the factors of given trinomial, first we will write x as the first term of each factor.
00:23
To find out the second term of each factor, first we have to find two integers whose product is 20.
00:33
And whose sum is 9.
00:37
So first we will list the pairs of factors of 20.
00:45
Factors of 20 are 1 and 20 to 10, 4 and 5.
01:11
Minus 1 minus 20 minus 2 minus 10 minus 4 minus 5 now we will find out the sum of factors 1 plus 20 is 21 2 plus 10 is 12 4 plus 5 is 9 minus 1 plus minus 20 is minus 21 minus 12 minus 9.
01:59
Here desired sum is 9.
02:17
So x squared plus 8x, 9x plus 20 factors are x plus 4 and x plus 5.
02:44
Now we will check these two factors are correct or not by using 4.
02:52
Foil multiplication method.
02:57
So factors are x plus 4 and x plus 5.
03:25
By using foil multiplication method, first f stands for product of first terms...