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(1) The product $(3-\sqrt{5})(4+2\sqrt{5})$ can be expressed in the form $a+b\sqrt{5}$, where a and b are integers. Find a+b.

 

(2)What is the sum of all possible values of x such that $2x(x-10)=-50$?

 

(3) The equation $y = -4.9t^2 + 23.8t$ describes the height (in meters) of a projectile launched from the ground at 23.8 meters per second. In how many seconds will the projectile first reach 28 meters in height? 

 

Thanks!

 Mar 4, 2021
 #1
avatar+236 
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1) Foil and get 2+2sqrt(5) so 2+2=4

 Mar 4, 2021
 #2
avatar+236 
+1

2) 2x^2-20=-50 

2x^2+30

x=

 Mar 4, 2021
 #3
avatar+236 
+1

3) https://web2.0calc.com/questions/help_44437

 Mar 4, 2021

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