14. 2x-1 = 0, x+7=0
x = 1/2, x = -7
15. x^2 + 3x - 10 = 0
(x + 5)(x - 2) = 0
x = -5, x = 2
16. x^2 - 25 = 0
(x-5)(x+5)
x = 5, x = -5
Answer: 2/3
Explanation: the difference between -14 and -10 is 4 and in fractions x/y. so we have 4/y. the difference between -18 and -12 is 6 so we have 4/6 but we can simplify that to 2/3.
The value of square root 86 is between 9 and 9.5
