line (-5,-10),(-1,5)
The slope between the two points is y2 -y1x2 -x1: 5 + 10-1 + 5
⇥ⓘ The numerator and the denominator are computed before the division: 5 + 10 = 15, -1 + 5 = 4
⇥ 154
The line passes through the first point with this slope: y = 154·(x + 5) -10
Compute the y-intercept b = y₁ - m*x₁: -10 -154·(-5)
⇥ⓘ Two minus signs cancel out, the product of two negative numbers is positive: -154·(-5) = 154·5
⇥ -10 + 154·5
⇥ⓘ Multiplying a fraction by a number multiplies its numerator: 154·5 = 15·54 = 754
⇥ -10 + 754
⇥ⓘ To add fractions, put them over the same denominator, then add the numerators: -10 + 754 = 4·(-10) + 754
⇥ 4·(-10) + 754
⇥ⓘ Multiplications are done before additions and subtractions. A single minus sign does not cancel out, the product of a negative number by a positive number is negative: 4·(-10) = -40
⇥ -40 + 754
⇥ⓘ The numerator and the denominator are computed before the division: -40 + 75 = 35
⇥ 354
▶Line:   y = 15x4 + 354