base: b
height: b
A = 1/2 (b · b) = 1/2(b²) = b²/2
sum is six less than area
b + b = 6 - ↔b²/2
2b = b²/2 - 6
4b = b² - 12 multiplied by 2 to clear the denominator
0 = b² - 4b - 12
0 = (b - 6)(b + 2)
0 = b - 6 0 = b + 2
b = 6 b = -2 (Negative so disregard)
A = b²/2 = (6)²/2 = 36/2 = 18
Answer: 18 units²