5b ≤ −15 solve the inequality for b.

Get the b all alone on one side of the inequality. To do this, we can divide both sides by 5.

5b / 5 ≤ -15 / 5
b ≤ -3

So, that means b has to be less than or equal to -3.

In interval notation it would look like [-3, -∞)

In a set builder notation: {x | x ∈ R, x ≤ -3}

Which is read as the set of all x, such that, x is a member of the real numbers and x is less than or equal to -3.

5b≤-15
Divided 5 for both side
5b/5≤-15/5
b≤-3. As a result, b≤-3. Hope it help!

Sin(a)+cos(a)+cot(a)-1=2(csc(x)+1)