Let real numbers a and B satisfy the following conditions: 3a2-10ab + 8b2 + 5a-10b = 0, and find the minimum value of u = 9A2 + 72B + 2
The second power of (2a + 3b-c)
The second power of (2a + 3b-c)
=[(2a+3b)-c]²
=(2a+3b)²-2c(2a+3b)+c²
=4a²+12ab+9b²-4ac-6bc+c²
How to square 2A minus 5A + 2
2a²-5a+2=(a-2)(2a-1)