+23254 3x² + 7x + 4 + ( ??? ) = 11x² - 15
Take these one term at a time:
The x² term: 3x² + ? = 11x² ---> must be 8x²
The x term: 7x + ? = 0x (no x-term on the right side) --> must be -7x
The number: 4 + ? = -15 ---> must be -19
So the missing part must be: 8x² - 7x - 19
