Again, with the positive last term, 28, and the negative middle term, −11y, we need two negative factors. Find two numbers that multiply 28 and add to −11.
|
|
|
y2−11y+28 |
| Write the factors as two binomials with first terms y. |
(y)(y) |
| Find two numbers that: multiply to 28 and add to −11. |
|
| Factors of 28 |
Sum of factors |
| −1,−28 −2,−14 −4,−7 |
−1+(−28)=−29 −2+(−14)=−16 −4+(−7)=−11∗ |
|
|
| Use −4,−7 as the last terms of the binomials. |
(y−4)(y−7) |
| Check: (y−4)(y−7)y2−7y−4y+28y2−11y+28✓ |
|