How do you solve #10t - 2t ^ { 2} = 0#?

1 Answer
Aug 27, 2017

See a solution process below:

Explanation:

First, factor a #t# from each term on the left giving:

#t(10 - 2t) = 0#

Now, solve each term on the left for #0# to find the values of #t#:

Solution 1:

#t = 0#

Solution 2:

#10 - 2t = 0#

#-color(red)(10) + 10 - 2t = -color(red)(10) + 0#

#0 - 2t = -10#

#-2t = -10#

#(-2t)/color(red)(-2) = -10/color(red)(-2)#

#(color(red)(cancel(color(black)(-2)))t)/cancel(color(red)(-2)) = 5#

#t = 5#

**The Solutions Are: #t = 0# and #t = 5#

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First, rewrite this equation in standard form:

#-2t^2 + 10t + 0 = 0#

We can now use the quadratic equation to solve this problem:

The quadratic formula states:

For #color(red)(a)x^2 + color(blue)(b)x + color(green)(c) = 0#, the values of #x# which are the solutions to the equation are given by:

#x = (-color(blue)(b) +- sqrt(color(blue)(b)^2 - (4color(red)(a)color(green)(c))))/(2 * color(red)(a))#

Substituting:

#color(red)(-2)# for #color(red)(a)#

#color(blue)(10)# for #color(blue)(b)#

#color(green)(0)# for #color(green)(c)# gives:

#t = (-color(blue)(10) +- sqrt(color(blue)(10)^2 - (4 * color(red)(-2) * color(green)(0))))/(2 * color(red)(-2))#

#t = (-color(blue)(10) +- sqrt(100 - 0))/(-4)#

#t = (-color(blue)(10) +- sqrt(100))/(-4)#

#t = (-color(blue)(10) - sqrt(100))/(-4)# and #t = (-color(blue)(10) + sqrt(100))/(-4)#

#t = (-color(blue)(10) - 10)/(-4)# and #t = (-color(blue)(10) + 10)/(-4)#

#t = (-20)/(-4)# and #t = 0/(-4)#

#t = 5# and #t = 0#