SOLUTION: what is the answer to this 5t^2 + 3t -9 =0 what is t? Thanx

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Question 293258: what is the answer to this 5t^2 + 3t -9 =0
what is t?
Thanx
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

5t%5E2%2B3t-9=0 Start with the given equation.


Notice that the quadratic 5t%5E2%2B3t-9 is in the form of At%5E2%2BBt%2BC where A=5, B=3, and C=-9


Let's use the quadratic formula to solve for "t":


t+=+%28-B+%2B-+sqrt%28+B%5E2-4AC+%29%29%2F%282A%29 Start with the quadratic formula


t+=+%28-%283%29+%2B-+sqrt%28+%283%29%5E2-4%285%29%28-9%29+%29%29%2F%282%285%29%29 Plug in A=5, B=3, and C=-9


t+=+%28-3+%2B-+sqrt%28+9-4%285%29%28-9%29+%29%29%2F%282%285%29%29 Square 3 to get 9.


t+=+%28-3+%2B-+sqrt%28+9--180+%29%29%2F%282%285%29%29 Multiply 4%285%29%28-9%29 to get -180


t+=+%28-3+%2B-+sqrt%28+9%2B180+%29%29%2F%282%285%29%29 Rewrite sqrt%289--180%29 as sqrt%289%2B180%29


t+=+%28-3+%2B-+sqrt%28+189+%29%29%2F%282%285%29%29 Add 9 to 180 to get 189


t+=+%28-3+%2B-+sqrt%28+189+%29%29%2F%2810%29 Multiply 2 and 5 to get 10.


t+=+%28-3+%2B-+3%2Asqrt%2821%29%29%2F%2810%29 Simplify the square root (note: If you need help with simplifying square roots, check out this solver)


t+=+%28-3%2B3%2Asqrt%2821%29%29%2F%2810%29 or t+=+%28-3-3%2Asqrt%2821%29%29%2F%2810%29 Break up the expression.


So the solutions are t+=+%28-3%2B3%2Asqrt%2821%29%29%2F%2810%29 or t+=+%28-3-3%2Asqrt%2821%29%29%2F%2810%29