Linear Equations 17F697
1. **State the problem:** Solve the system of linear equations:
$$10x + 4y = 15$$
$$15x - 8y = 33$$
2. **Formula and method:** We will use the elimination method to solve for $x$ and $y$. The goal is to eliminate one variable by making the coefficients of $y$ (or $x$) opposites.
3. **Eliminate $y$:** Multiply the first equation by 2 to match the coefficient of $y$ in the second equation:
$$2(10x + 4y) = 2(15) \Rightarrow 20x + 8y = 30$$
4. **Add the new equation to the second equation:**
$$20x + 8y = 30$$
$$15x - 8y = 33$$
Adding gives:
$$20x + 8y + 15x - 8y = 30 + 33$$
$$35x = 63$$
5. **Solve for $x$:**
$$x = \frac{63}{35} = \frac{9}{5} = 1.8$$
6. **Substitute $x=1.8$ into the first original equation:**
$$10(1.8) + 4y = 15$$
$$18 + 4y = 15$$
7. **Solve for $y$:**
$$4y = 15 - 18 = -3$$
$$y = \frac{-3}{4} = -0.75$$
**Final answer:**
$$x = 1.8, \quad y = -0.75$$