line (-2,8),(4,6)
The slope between the two points is y2 -y1x2 -x1: 6 -84 + 2
⇥ⓘ The numerator and the denominator are computed before the division: 6 -8 = -2, 4 + 2 = 6
⇥ -26
⇥ⓘ We simplify the fraction by dividing the numerator and the denominator by 2, their greatest common divisor: -26 = -1·23·2 = -13
⇥ -13
The line passes through the first point with this slope: y = -13·(x + 2) + 8
Compute the y-intercept b = y₁ - m*x₁: 8 -(-13·(-2))
⇥ 8 -13·2
⇥ⓘ Multiplying a fraction by a number multiplies its numerator: 13·2 = 1·23 = 23■To add fractions, put them over the same denominator, then add the numerators: 8 -23 = 3·8 -23
⇥ 3·8 -23
⇥ⓘ Multiplications are done before additions and subtractions: 3·8 = 24
⇥ 24 -23
⇥ⓘ The numerator and the denominator are computed before the division: 24 -2 = 22
⇥ 223
▶Line:   y = -x3 + 223