the sum of two numbers is -17. Their product is 66. Find the numbers
A = one number
B = the other number
A + B = -17 ← Call this eq1
A = - B - 17
A x B = 66 ← call this eq2
A = 66/B ← eq3
substitute eq3 to eq1
66/B + B = -17
66 + B² = -17B
B² + 17B + 66 = 0
B = [-b ±√B² - 4ac]/2a
B = [-17 ±√(-17)² - 4(66)] / 2
B = -17 ±√289 - 264 ]/2
B = [ -17 ± √25]/2
B = [ -17 + 5]/2
B = -12 /2
B = - 6
Substitute B = -6 to eq 2
A x B = 66 ← call this eq2
A = 66 / - 6
A = - 11