(b-6)b-(5-b)^2 = b²-6b-(25+b²-10b)= b²-6b-25-b²+10b=4b-25
Sin a cos b = 1/2 * (sin(a - b) + sin(a + b))
sin 7x cos 3x = 1/2 * (sin 4x + sin 10x)
∫ 1/2 * (sin 4x + sin 10x) dx = 1/2 ∫ sin 4x dx + 1/2 ∫ sin 10x dx = -1/8 cos 4x - 1/20 cos10x + C
x+2/9=7/9 y - 5/7= 1/7 3 5/8 - z =2
5,1/6+3,1/6=50/6=8,2/6=8,1/3
100-100%
13-x%
x=(13×100)/100=13%