Factorise: a² + 19a + 78 using middle term splitting method
Answers
Step-by-step explanation:
Correct Question :-
Factorise a² + 19a + 78
Solution:-
Factoring a²-19a+78
The first term is, a² its coefficient is 1 .
The middle term is, -19a its coefficient is -19 .
The last term, "the constant", is +78
Step-1 : Multiply the coefficient of the first term by the constant 1 • 78 = 78
Step-2 : Find two factors of 78 whose sum equals the coefficient of the middle term, which is -19 .
-78 + -1 = -79
-39 + -2 = -41
-26 + -3 = -29
-13 + -6 = -19 That's it
Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above, -13 and -6
a² - 13a - 6a - 78
Step-4 : Add up the first 2 terms, pulling out like factors :
a • (a-13)
Add up the last 2 terms, pulling out common factors :
6 • (a-13)
Step-5 : Add up the four terms of step 4 :
(a-6) • (a-13)
Which is the desired factorization