To solve the quadratic equation \( x^2 - 13x + 42 = 0 \) by grouping, we need to split the middle term of \(-13x\) into two terms that add up to \(-13\) and multiply to \(42\) (the constant term).
We need to find two numbers, \(a\) and \(b\), such that:
- \(a + b = -13\)
- \(a \cdot b = 42\)
Let's consider the factors of \(42\):
- \(1 \cdot 42\)
- \(2 \cdot 21\)
- \(3 \cdot 14\)
- \(6 \cdot 7\)
Now we will check these pairs to see which pair adds up to \(-13\):
- \(1 + 42 = 43\) (not suitable)
- \(-1 + (-42) = -43\) (not suitable)
- \(2 + 21 = 23\) (not suitable)
- \(-2 + (-21) = -23\) (not suitable)
- \(3 + 14 = 17\) (not suitable)
- \(-3 + (-14) = -17\) (not suitable)
- \(6 + 7 = 13\) (not suitable)
- \(-6 + (-7) = -13\) (suitable)
Thus, the two numbers that can be used to split the middle term are \(-6\) and \(-7\).
So, the answer is: -6, -7