Question

a, Cho hàm số \(y = f ( x )\) = \((m^2 - 2 )\)\(x^2+2(m^2-1)\) . Tìm m nếu \(f(-2) = 140\)

b, Cho hàm số \(y=h(x)=(n^3-2)x+2(n^3-1)-3\) . Tìm n nếu \(h(3)-2h(1)=11\)

Answer 1

a, f(-2)=(m^2-2).(-2)^2+2(m^2-1)=140

=(m^2-2).4+2m^2-2=140

=4m^2-8+2m^2-2=140

=6m^2-10=140

=6m^2=150

=m^2=25

=> m=+-5

Answer 2

b, h(3)-2h(1)=(n^3-2).3+2.(n^3-1)-3-2[(n^3-2).1+2(n^3-1)-3]=11

=3n^3-6+2n^3-2-3-2n^3+4-4n^3+4+6=11

=-n^3+3=11

=-n^3=8(loại)

vậy ko tìm đc n

Answer 3

a, Ta có : \(f\left(-2\right)=\left(m^2-2\right).\left(-2\right)^2+2.\left(m^2-1\right)=140\)

\(=4m^2-8+2m^2-2=140\)

\(=\left(4m^2+2m^2\right)+\left(-8-2\right)=140\)

\(=6m^2=140-\left(-10\right)\)

\(\Leftrightarrow6m^2=150\)

\(\Leftrightarrow m^2=25\)

\(\Leftrightarrow m=\pm5\)

Vậy : \(m=\pm5\) nếu \(f\left(-2\right)=140\)