3a² + 11a - 42

this is factoring in algebra 2 (high school)

To factor,

[[[

1) First multiply coefficient of a² and constant no,

That is,

3 * (-42) = -126

Since the resultant no is negative, you should find two such factors of 126 which will give us the coefficient of a (=11) on subracting those factors.

2) Find the factor

126=2*3*3*7

=18*7

18 and 17 are factors of 126

Also, 18-7 = 11.

So they are required factors for factoring,

]]]

Once you have understood above steps you can solve on your own. All you need to do is split 11 into factors, take common terms and you will get answer.

Answer:

3a²+11a-42

=3a² + (18-7) a - 42

=3a²+18a-7a-42

=3a (a+6) - 7 (a+6)

= (a+6) (3a-7)