Question

Fill in the missing numbers to complete the linear equation that gives the rule for this table.

х y
2 -36
3 -33
4 -30
5 -27

Y= ___x - ___

Answer 1

y = 3x - 42

Explanation:

• The equation of a line if y = mx + c
• First, choose two of the x values with their respective y values
• I’ll choose 2 & -36 and 3 & -33
• We need to find the gradient of this line (which is the m in y = mx + c)
• We can do this by finding the difference in the y values and divide this by the difference in the x values
• So this would be
  `(-33--36)/(3-2) = (3)/(1)=3`
• So far we have y = 3x + c
• Using one of the x values and their respective y value, substitute these values into the formula
• I’ll choose 4 & -30
• -30 = 3 × 4 + c
• -30 = 12 + c
• c = -30 - 12 = -42
• So the equation is y = 3x - 42!