Vector Projection 314F9B
1. **Stating the problem:**
Given points Tink M $(2, -7)$ and Oleh $(3, 4)$, and a vector equation $8x + 3y = 9$, find the projection of the vector from Tink M to Oleh onto the vector $(7, -5)$.
2. **Understanding the problem:**
We want to find the projection of vector $\vec{A} = \overrightarrow{TinkM \, to \, Oleh}$ onto vector $\vec{B} = (7, -5)$.
3. **Calculate vector $\vec{A}$:**
$$\vec{A} = (3 - 2, 4 - (-7)) = (1, 11)$$
4. **Formula for projection:**
The projection of $\vec{A}$ onto $\vec{B}$ is given by:
$$\text{proj}_{\vec{B}} \vec{A} = \frac{\vec{A} \cdot \vec{B}}{\|\vec{B}\|^2} \vec{B}$$
where $\vec{A} \cdot \vec{B}$ is the dot product and $\|\vec{B}\|$ is the magnitude of $\vec{B}$.
5. **Calculate dot product:**
$$\vec{A} \cdot \vec{B} = (1)(7) + (11)(-5) = 7 - 55 = -48$$
6. **Calculate magnitude squared of $\vec{B}$:**
$$\|\vec{B}\|^2 = 7^2 + (-5)^2 = 49 + 25 = 74$$
7. **Calculate projection vector:**
$$\text{proj}_{\vec{B}} \vec{A} = \frac{-48}{74} (7, -5) = \left(\frac{-48 \times 7}{74}, \frac{-48 \times (-5)}{74}\right) = \left(\frac{-336}{74}, \frac{240}{74}\right)$$
8. **Simplify fractions:**
$$\frac{-336}{74} = \frac{-168}{37}, \quad \frac{240}{74} = \frac{120}{37}$$
9. **Final answer:**
The projection vector is:
$$\boxed{\left(-\frac{168}{37}, \frac{120}{37}\right)}$$
This vector represents the shadow (projection) of $\vec{A}$ on $\vec{B}$.