Hello,
We have : (a + b)² = a² + 2ab + b²
4x² + 20x + 25 = (2x)² + 2 × 2x × 5 + 5² = (2x + 5)² → answer B
Here, we have a = 2x and b = 5 !
When you can divide, or multiply by the same number. for numerator and denominator.
3/4 X 10= $7.50
Because 3/4 is 75%, 10 is the original price. And 75% times 10 is 7.50<span />
16 cm -10 days
1 cm --- x days
x=1*10/16=5/8=0.625 days
