To solve your question step by step:
Part A:
To write the quadratic equation \( x^2 - 18x + c = -80 + c \) in the form of a perfect square trinomial, we need to complete the square for the equation on the left side.
- The left side of the equation is: \[ x^2 - 18x + c \]
- To complete the square for \( x^2 - 18x \):
- Take half of the coefficient of \( x \) (which is -18), square it: \[ \left(-\frac{18}{2}\right)^2 = (-9)^2 = 81 \]
- So we can express the equation as: \[ x^2 - 18x + 81 \]
- Therefore, for \( c \) to make the left side a perfect square trinomial, we have: \[ c = 81 \]
Part B:
Now, we can factor the perfect square trinomial: \[ x^2 - 18x + 81 = (x - 9)^2 \] So we rewrite the equation as: \[ (x - 9)^2 = -80 + 81 \] This simplifies to: \[ (x - 9)^2 = 1 \]
Part C:
To find the solutions for \( x \):
- We take the square root of both sides: \[ x - 9 = \pm 1 \]
- This gives us two equations:
- \( x - 9 = 1 \)
- \( x - 9 = -1 \)
From \( x - 9 = 1 \): \[ x = 9 + 1 = 10 \]
From \( x - 9 = -1 \): \[ x = 9 - 1 = 8 \]
The lesser number is \( \boxed{8} \).
Part D:
The greater number from the solutions we found is \( \boxed{10} \).
In summary:
- Part A: \( c = 81 \)
- Part B: Equation is \( (x - 9)^2 = 1 \)
- Part C: Lesser solution \( x = 8 \)
- Part D: Greater solution \( x = 10 \)