1. **State the problem:** Solve the simultaneous equations:
$$7x + 11y = -5$$
$$4x + 3y = 7$$
2. **Choose a method:** We will use the elimination method to solve for $x$ and $y$.
3. **Eliminate one variable:** Multiply the first equation by 3 and the second equation by 11 to align coefficients of $y$:
$$3(7x + 11y) = 3(-5) \Rightarrow 21x + 33y = -15$$
$$11(4x + 3y) = 11(7) \Rightarrow 44x + 33y = 77$$
4. **Subtract the first new equation from the second:**
$$\cancel{33y} + 44x - (21x + \cancel{33y}) = 77 - (-15)$$
$$44x - 21x = 77 + 15$$
$$23x = 92$$
5. **Solve for $x$:**
$$x = \frac{92}{23} = 4$$
6. **Substitute $x=4$ into one original equation to find $y$:** Using $4x + 3y = 7$:
$$4(4) + 3y = 7$$
$$16 + 3y = 7$$
7. **Isolate $y$:**
$$3y = 7 - 16$$
$$3y = -9$$
8. **Solve for $y$:**
$$y = \frac{-9}{3} = -3$$
**Final answer:**
$$x = 4, \quad y = -3$$
Simultaneous Equations 90D314
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