Now, this quadratic expression does not resemble any of the special product. So now, let's try to factorize using a different method. That is the cross method. So that let's look at this term, this constant. It can be expressed as 1 times 8, 2 times 4. So we are going to use the cross method. First of all, we draw this. A square is same as A times A. A times A will give us A square. Compare these two terms, this is likely to result as 6. Very sum up the numbers. So let's try 2 and 4. So A times 2 will give us 2 A. A times 4 will give us 4 A. To get 6 A, which is positive, it means these two terms are positive. If this is positive, it means this is positive. If here, it's positive, it also means it's positive. Let's check. Positive 2 times positive 4 will give us positive 8, which is the same as this. Therefore, it is factorized and we get A plus 2 times A plus 4. If we were to expand these two factors, we should get A square plus 6 A plus 8. Now let's try another one. We have x square minus 13x plus 40. Slice down the possible pairs of factors. 1 times 40, 2 times 20, 4 times 10, 5 times 8. Among the 4 pairs, 5 times 8. This pair is likely to give us 13. We should test up with this pair afterwards. x square is same as x times x will give us x square. 40, so we try 5 times 8. Now, 5 and x will give us 5 x. Here, we get 8x. From 5x and 8x, we could get negative 13x if both are negative, which will translate to x times 95 to give us 95x and x times negative 8 to give us negative 8x. Negative 5 times negative 8 will give us positive 40. Let's check. Correct. Therefore, we'll vectorize. You will get x minus 5, which is here. And this one, x minus 8 answer. Let's try to vectorize this using the cross method in 1 minute. 20 can be expressed as 1 times 20, 2 times 10 and 4 times 5. To get 9m, we'll check out with this pair. Let's try. m square is same as m times m, which will give us m square. 20, we can try 4 times 5. m times 4 gives us 4m. m times 5, 5m. We need positive 9m, which means I will have positive 4m and positive 5m to give me positive 9m. If this is positive, it means this is positive and this is positive. Multiply together we get positive 20. Let's compare and check. Yes, it's correct. Therefore, the two vectors are m plus 4 and m plus 5. To check, we can expand this and we should get m square plus 9m plus 20.