Suppose that the functions s and f are defined for all real
Solution
s(x)=3x2,t(x)=2x
(s-t)(x)=s(x) - t(x)
(s-t)(x)=3x2-2x
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(s+t)(x)=s(x) + t(x)
(s+t)(x)=3x2+2x
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(s*t)(x)=s(x) * t(x)
(s*t)(x)=3x2*2x
(s*t)(x)=6x3
(s*t)(-1)=6(-1)3
(s*t)(-1)=-6
