y=5-x
x|1 -1 2
y|4 6 3
y=x-1
x|1 -1 4
y|0 -2 3
1)140x-(25x^2-70x+49)
140x-25x^2+70x-49
210x-25x^2-49
-25x^2+210x-49
2)(√2*11 - √7*13)
√22-√91
<span>cos a- cos3a + 2 sin 2a=-2sin(2a)*cos(-a)+2 sin 2a=2 sin 2a(1-cos(a))</span>