1. **State the problem:** Solve the equation $8y + 7 + 7y + 8 = 90$ for $y$. 2. **Combine like terms:** Group the terms with $y$ and the constant terms. $$8y + 7y + 7 + 8 = 90$$ $$15y + 15 = 90$$ 3. **Isolate the variable term:** Subtract 15 from both sides. $$15y + \cancel{15} - \cancel{15} = 90 - 15$$ $$15y = 75$$ 4. **Solve for $y$:** Divide both sides by 15. $$\frac{15y}{\cancel{15}} = \frac{75}{\cancel{15}}$$ $$y = 5$$ 5. **Final answer:** The solution to the equation is $y = 5$.