I hope this helps you
x=42.8+6.9
x=49.7
<span>-2x^2-x+7=0
Variable with the highest degree's (exponent) constant, -2 is a, next variable's constant, -1 is b, the constant or number without a variable, 7 is c
using substitution put the numbers into the formula
</span>(-b±√(b^(2)-4ac))/(a^(2))
(-(-1)±√((-1)^(2)-4(-2)(7))/((-2)^(2)) simplify
(1±√(1+56))/4
1±√(57)/4 is your answer
160/140 = x/56
cross multiply
(140)(x) = (160)(56)
140x = 8960
x = 8960/140
x = 64 lbs <== Vince's weight on the other planet
25 - 5x = 80
+ 5x + 5x
25 = 5x + 80
- 80 -80
-55 = 5x
-55/5 = 11
x = 11
Hope I helped!
Let me know if you need anything else!
~ Zoe