
Nick Y.
asked 10/04/21Help me on quadratics
27x-54(x-2)=9x^2-18x
4r^3+4r^2=9(r+1)
help me I am stuck
1 Expert Answer
(1) 27x-54(x-2) = 9x2-18x
27x-54x+108 = 9x2-18x
Move the left side of the equation to the right and change the sign.
0 = 9x2-18x - 27x+54x-108
combine like terms.
0 = 9x2+9x-108
Factor out 9
0 = 9( x2+x-12 )
Divide 9 both side:
0 = x2+x-12
Factor:
0 = (x+4) (x-3)
x=-4 or x =3
(1) 4r3+4r2=9(r+1)
Factor the left side and move the right side to the left.
4r2(r+1)-9(r+1)=0
(4r2-9)(r+1) = 0
Split into 2 equations (you got 3 solutions for r):
4r2-9 = 0 r+1 = 0
4r2 = 9 r= -1
r2 = 9/4
r = ± 3/2
Nick Y.
Second to last step , you square root the r right ?10/04/21
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Joel L.
10/04/21