To solve the quadratic equation \( x^2 - 13x + 42 = 0 \) by grouping, we need to split the middle term, which is \(-13x\), into two terms that add up to \(-13\) and multiply to \(42\).
We are looking for two numbers \(a\) and \(b\) such that:
- \( a + b = -13 \)
- \( a \cdot b = 42 \)
Let's find pairs of factors of \(42\):
- \(1\) and \(42\)
- \(2\) and \(21\)
- \(3\) and \(14\)
- \(6\) and \(7\)
Now let's consider the sums of these factor pairs:
- \(1 + 42 = 43\)
- \(2 + 21 = 23\)
- \(3 + 14 = 17\)
- \(6 + 7 = 13\)
Since we need them to sum to \(-13\), we can take the negatives of each:
- \(-1\) and \(-42\) (Sum = -43)
- \(-2\) and \(-21\) (Sum = -23)
- \(-3\) and \(-14\) (Sum = -17)
- \(-6\) and \(-7\) (Sum = -13)
The pair \(-6\) and \(-7\) successfully sums to \(-13\) and multiplies to \(42\).
Therefore, the two numbers that complete the grouping step are \(-6\) and \(-7\).
Answer: -7, -6