Answer:
The value of u is 6
Step-by-step explanation:
The rule of the slope of a line is [tex]m=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}[/tex] , where
[tex](x_{1},y_{1})[/tex] and [tex](x_{2},y_{2})[/tex] are two points on the line
Let us use this rule to solve the question
∵ The slope of the line is -3
∴ m = -3
∵ The two points on the line are (-5, u) and (-4, 3)
∴ [tex]x_{1}[/tex] = -5 and [tex]x_{2}[/tex] = -4
∴ [tex]y_{1}[/tex] = u and [tex]y_{2}[/tex] = 3
→ Substitute these values in the rule of the slope above
∴ [tex]-3=\frac{3-u}{-4-(-5)}[/tex]
∴ [tex]-3=\frac{3-u}{1}[/tex]
→ By using cross multiplication
∴ -3 × 1 = 3 - u
∴ -3 = 3 - u
→ Add u to both sides to move u from the right side to the left side
∴ -3 + u = 3 - u + u
∴ -3 + u = 3
→ Add 3 to both sides to move -3 from the left side to the right side
∴ -3 + 3 + u = 3 + 3
∴ u = 6
The value of u is 6
