True False Geometry
1. We are asked to determine if the given statements are TRUE or FALSE and justify the answers.
(i) Distance between points $(3x, -3x)$ and $(-x, -6x)$ is $-5x$ if $x<0$.
Distance formula: $$d = \sqrt{(3x - (-x))^2 + (-3x - (-6x))^2} = \sqrt{(4x)^2 + (3x)^2} = \sqrt{16x^2 + 9x^2} = \sqrt{25x^2} = 5|x|$$
If $x<0$, then $|x| = -x$. So, $$d = 5(-x) = -5x$$
**Answer: TRUE** because the distance simplifies to $-5x$ for $x<0$.
(ii) Graph of $x = \sqrt{y - 1}$: Check intercepts.
-x intercept: Set $y=0$, then $x = \sqrt{0 - 1} = \sqrt{-1}$ which is not real.
-y intercept: Set $x=0$, then $0 = \sqrt{y - 1} \implies y - 1 = 0 \implies y = 1$
So $y$ intercept is at $(0, 1)$.
**Answer: FALSE** because there is no $x$-intercept but there is a $y$-intercept.
(iii) Midpoint $M(x, y)$ between $(3, 4)$ and $(k, 6)$:
$$x = \frac{3 + k}{2}, \quad y = \frac{4 + 6}{2} = 5$$
Given $x + y = 1$, substitute:
$$\frac{3 + k}{2} + 5 = 1 \implies \frac{3 + k}{2} = 1 - 5 = -4 \implies 3 + k = -8 \implies k = -11$$
Given statement says $k=11$.
**Answer: FALSE** because $k$ equals $-11$, not $11$.
(iv) Graph $y = -\sqrt{x + 1}$.
Find intercepts:
-x intercept set $y=0$: $$0 = -\sqrt{x + 1} \implies \sqrt{x + 1} = 0 \implies x + 1 = 0 \implies x = -1$$
So $x$ intercept is $(-1,0)$.
-y intercept set $x=0$: $$y = -\sqrt{0 + 1} = -1$$
So $y$ intercept is $(0,-1)$.
Midpoint $(m,n)$ of these:
$$m = \frac{-1 + 0}{2} = -\frac{1}{2}, \quad n = \frac{0 + (-1)}{2} = -\frac{1}{2}$$
Sum:
$$m + n = -\frac{1}{2} - \frac{1}{2} = -1 \neq 0$$
**Answer: FALSE** because $m+n = -1$, not $0$.
Final answers:
(i) TRUE
(ii) FALSE
(iii) FALSE
(iv) FALSE