-2.5 and 4
You can get this by factoring to the equation (2x + 5)(x - 4)
Answer:

Step-by-step explanation:
After every Half life , Half of the mass is left.
After 1st Half life = 100 g / 2 = 50 g
After 2nd Half life = 50 / 2 = 25 g
After 3rd Half life = 25 / 2 = 12.5 g
After 4th Half life = 12.5 / 2 = 6.25 g
![\rule[225]{225}{2}](https://tex.z-dn.net/?f=%5Crule%5B225%5D%7B225%7D%7B2%7D)
Hope this helped!
<h3>
~AH1807</h3>
Answer:
The answer is 8
Step-by-step explanation:
It costs £1 to throw a party
Fourth test mark should be 86
85 + 82 + 75 + 86 = 328
328 divide by 4 (as there are four tests) = 82