Question

If the line joining (3x, x+1) and (11,12) has a slope of 4 what is the value of x​

Answer 1

Answer:

x = 3

Step-by-step explanation:

$(3x,\: x +1)=(x_1, \:y_1)$

$(11,\: 12)=(x_2, \:y_2)$

$slope = \frac{y_2 - y_1}{x_2 - x_1} \\ \\ 4 = \frac{12 - (x + 1)}{11 - 3x} \\ \\ 4 = \frac{12 - x - 1}{11 - 3x} \\ \\ 4 = \frac{11 - x}{11 - 3x} \\ \\ 4(11 - 3x) = 11 - x \\ \\ 44 - 12x = 11 - x \\ \\ 44 - 11 = 12x - x \\ \\ 33 = 11x \\ \\ x = \frac{33}{11} \\ \\ \huge \red{ \boxed{x = 3}}$