tolong pleaseeee tolongggggggggg

36
cosx = cos14°
x = 14° + k.360°
x = -14° + k.360
x = {14° , 346°}

37
cos23 cos7 - sin23 sin7
= cos(23 + 7)
= cos30
= (1/2)√3

39
f(x) = x⁶ - 2x³ + x + 10

f(-4)
= (-4)⁶ - 2(-3)³ + (-4) + 10
= 4096 - (-54) + 6
= 4156

40
x³ - x² - 5x - 3
= (x - 3)(x² + 2x + 1)
= (x - 3)(x + 1)(x + 1)