Evaluate ab + 3c when a=-6, b=-2, and c=5

Do it step by step
ab+3c
(-6)(-2)+3(5)
A negative times a negative is positive. (-)(-)=+
12+3(5)
12+15
=27

The Pythagorean theorem states that:
c^2=a^2+b^2
where;
c=hypotenuse
a and b are the legs
Therefore, testing the triangle whose dimensions are: 11,60 and 61 taking
11 and 60 as the legs and 61 as the hypotenuse, we shall have:
61^2=11^2+60^2
3721=121+3600
3721=3721
since the LHS=RHS it implies that the triangle satisfies the Pythagorean theorem hence we conclude that it is a right angled triangle