49x²-16=0
49x²=16
x²=16/49
x = - 4/7 , 4,7
(√32-√150): √2 +7√3 =√ (16*2) -√(25*2*3 )/√2 + 7√3 =
(4√2 -5√2*√3)/√2 + 7√3= √2(4 - 5√3)/√2 +7√3 =4 - 5√3 +7√3 =2 +2√2 =2(1+√2).
<span>sin x -cos x =n</span>
Б)
2x^2+9x+7<=0
D=81-56=25
x1=((-9)+5)/4=-1
x2=((-9)-5)/4=7/2
2x+5<=0
x<=-5/2