2tgx-5/tgx=3
2tg²x-3tgx-5=0,tgx≠0
tgx=a
2a²-3a-5=0
D=9+40=49
a1=(3-7)/4=-1⇒tgx=-1⇒x=-π/4+πn,n∈z
a2=(3+7)/4=2,5⇒tgx=2,5⇒x=artg2,5+πk,k∈z
- 3( x + 8) = 6 × 4
- 3x - 24 = 24
- 3x = 24 + 24
- 3x = 48
3x = - 48
x = - 48/3
x = - 16
1. <span>((a+b)-(a-b))*((a+b)+(a-b))*(1/a+1/b) = (a+b-a+b)*(a+b+a-b)*(1/a+1/b) = 2a*2b*(a+b)/ab = 4a+4b = 4(a+b)</span>
2. (1,8<span>·3</span>)(10-3<span>·105</span>)=5,4
3. -164
4. 3,3
5. 6
6. А
7. Б