√2cos²x=cosx
√2cos²x-cosx=0
√2*cosx(cosx-√2/2)=0
cosx=0
x=π/2+π*n
cosx-√2/2=0
cosx=√2/2
x=+-π/4+2π*n
Б) [-7*π/2; -2π]
x=-7π/2
x=-3π
x=-2π
x=-π/4-2π=-9π/4
24.
а) a + b / 5
б) 6a^2 - 14a^2 / x = -8a^2 / x
в) a + b - b / 8 = a / 8
г) 3a - x + 2x / b = 3a + x / b
25.
а) b - b - 2a / 3a = -2a / 3a
б) 14c - 35 + 5 -2c / 6c = 12c - 30 / 6c = 2c - 30
в) 3a - b - 2a + 6b + a -5b / 4a = 2a / 4a = 1/2
г) 2x - 3y + 11y - 4x -2x + 8y / 4xy = 4x + 16y / 4xy
(m-3n)(m+3n)+(3n-4)²=m²-9n²+9n²-24n+16=m²-24n+16