SOLUTION: use factoring and the zero product property to solve the following problem 9r^2-30r+21=-4
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Question 985949
:
use factoring and the zero product property to solve the following problem
9r^2-30r+21=-4
Answer by
ankor@dixie-net.com(22740)
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9r^2 -30r + 21 = -4
add 4 to both sides
9r^2 - 30r + 21 + 4 = 0
9r^2 - 30r + 25 = 0
factors (a perfect square) to
(3r - 5)(3r - 5) = 0
solutions
3r = 5 twice
r = 5/3 and r = 5/3