1)(4-1/4)·8/15=(16/4-1/4)·8/15=15/4·8/15=8/4=2
2)f(1)=5; 1+m=5⇒m=4
3)x²+x+1=1⇔x²+x=0⇔x(x+1)=0⇔x=0;x=-1
4)(n-2)(n-4)=0⇔n=2;n=4 ecuatia are 2 solutii
deci, P(A)=2/9
5)MN=4;MP=5;PN=3
P=4+5+3=12
6) sin120°=sin(90°+30°)=-cos30° ;sin²120°=(-cos30°)²=cos²30°
sin²120°-cos²30°=cos²30°-cos²30°=0
