Ответ:
21.5
Объяснение: = 4+ 10а + а² + 25 -а² = 29+10а = 29+10*(-3/4) = 21.5
2x²+14x=0
2x(x+7)=0
2x=0
x=0 или x+7=0
x=-7
50=100
X=120
X=50*120:100
X=60
200:60=3 (ост.20)
6log(-x,1/2) - log(x^2,1/2)^2 = 2
6 log(-x,1/2) - 4log(-x,1/2)^2 = 2
t = log(-x,1/2)
2t^2 - 3t + 1 = 0
D = 9 - 8 = 1
t1 = (3+1)/4 = 1
t2 = (3-1)/4 = 1/2
log(-x,1/2) = 1 => x = -1/2
log(-x,1/2) = 1/2 => x = -корень(2)/2
<span>a)y=2sinx+cosx если х=-п/2; x=п/6
y=2sin-</span>π/2+cos -π/2=-2+0=-2
y=2sinπ/6+cosπ/6=1+√3/2
<span>
б)y=cos x-x</span>²<span>если x=-п/3; x=-п
</span> y=cosπ/3-π²/9=1/2-π²/9
y=cos-π-π²=-1-π²
<span>в)y=2cos(x-п/4)-1,если x=-п/2;x=п/4
</span> y=2cos(-π/2-π/4)-1=2cos(3π/4)-1=-√2/2-1
y=2cos0-1=2-1=1