Factorize 3x² + 10x + 7.

For factorizing, an expression split the middle term in such a way that the product of the coefficients of the new terms is equal to the product of the coefficients of the first and last terms in the expression.

Here, product of co-effs of first and last terms = 7 × 3 = 21

So, if the middle term 10x is split into two terms say ax, bx, then

a + b = 10 and ab = 21.

Observe that values 3 and 7 satisfy these equations.

⇒ 3x² + 10x + 7 = 3x² + 3x + 7x + 7

Observe that 3x is common for the first two terms and 7 is

common for the next two terms.

⇒ 3x² + 3x + 7x + 7 = 3x(x + 1) + 7(x + 1)

Now, (x + 1) is the common term.

∴ 3x² + 10x + 7 = (x + 1)(3x + 7)

Hence, the factors of 3x² + 10x + 7 are (x + 1) and (3x + 7).