Following with the extra hint that x = 82.03 m
There are 2 ways to approach the question, but although I prefer to group up x first before plugging value, having that -0.05x^2 to group up is too annoying:
Plug x = 82.03
=> Y = -0.05*(82.03^2) + 4.5*82.03 - 6.5
= -336.446045 + 369.135 - 6.5
= 26.188955 m
Please take the time and understand the answer instead of just looking at the final result.
Also I know the number is very long, but that's the question's fault. <span>¯\_(ツ)_/¯</span>
-2x +7 = 3x - 8
Move the variable to the left-hand side and change its sign
-2x -3x+ 7 = -8
Move the constant to the right-hand side and change its sign
-2x -3x = -8 -7
Collect like terms
-5x = -15
Divide both sides of the equation by -5
x=3
It would take about 5 hours for them two to work together, because if you add 2+3 you will get 5 and they are asking in total.
Calculator method:
75% as a decimal is 75/100= 0.75. So an increase of 75% is 100% + 75% which is the same as 1+0.75= 1.75. This is your multiplier, so now just do 8×1.75=$14
Non-calculator method:
Find out what 50% of 8 is, this can be done by halving 8 which gives you 4. Now find out what 25% of 8 is, this can be done by halving what you got for 50% (4), so 25% of 8 is 2. 50%+25%=75%, so (4+2)=6 is 75% of 8. Now just do 8+6= $14
The answer is in bold.
