Why 20

Question

function calcD(a, b, c) {
return b*b - 4*a*c;
}

var test = calcD(-4, 2, 1);
alert(test); // 20

Answer 1

a = -4, b = 2, c = 1

b * b - 4 * a * c
= (2 * 2) - (4 * -4 * 1)
= (4) - (-16)
= 4 + 16
= 20

Answer 2

a = -4
b = 2
c = 1
b*b - 4*a*c === 2*2 - 4*(-4)*1
4 + 16 = 20

Answer 3

yes - and - will be plus it's mathematics but I don't knew which in js working look like it thx so much