document.write( "Question 1031362: 1. the larger leg of a right triangle is 3cm longer than its smaller leg. The hypotenuse is 6 cm longer than the smaller leg. How many centimeters long is the smaller leg? \r
\n" ); document.write( "\n" ); document.write( "2. the function f(t)= -5t^2+20t+60 models the approximate height of an object t seconds after its launched. How many seconds does it take the object to hit the ground? \r
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Algebra.Com's Answer #646122 by LinnW(1048)\"\" \"About 
You can put this solution on YOUR website!
1. s = length of smaller leg
\n" ); document.write( "l = larger leg
\n" ); document.write( "h = hypotenuse
\n" ); document.write( "l = s + 3
\n" ); document.write( "h = s + 6
\n" ); document.write( "\"s%5E2+%2B+l%5E2+=+h%5E2\"
\n" ); document.write( "substituting
\n" ); document.write( "\"s%5E2+%2B+%28s%2B3%29%5E2+=+%28s%2B6%29%5E2\"
\n" ); document.write( "s^2 + s^2 + 6s + 9 = s^2 + 12s + 36
\n" ); document.write( "add -s^2 to each side
\n" ); document.write( "s^2 + 6s + 9 = 12s + 36
\n" ); document.write( "add -12s to each side
\n" ); document.write( "s^2 - 6s + 9 = 36
\n" ); document.write( "add -36 to each side
\n" ); document.write( "s^2 - 6s - 27 = 0
\n" ); document.write( "(s - 9)(s + 3) = 0
\n" ); document.write( "So s = 9 , s cannot be -3 since this would be a negative length.
\n" ); document.write( "2.
\n" ); document.write( "f(t)= -5t^2+20t+60
\n" ); document.write( "We want to find the values for t where f(t) = 0 .
\n" ); document.write( "0 = -5t^2+20t+60
\n" ); document.write( "divide each side by -5
\n" ); document.write( "0 = t^2 - 4t - 12
\n" ); document.write( "0 = (t - 6)(t + 2)
\n" ); document.write( "So t = 6. t = -2 does not work since we cannot have negative time.
\n" ); document.write( "Confirm by substituting in our original equation.
\n" ); document.write( "0 = -5(6)^2+20(6)+60
\n" ); document.write( "0 = -5(36)+20(6)+60
\n" ); document.write( "0 = -180 +120 + 60
\n" ); document.write( "0 = 0
\n" ); document.write( "So it checks out.
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