Answer:
x^2 - 6x -18 is the same so you can write
x^2 - 6x -18 = ( x^2 - 8x - 15 = 3)
Step-by-step explanation:
When we subtract 3 each side we get -18 as -15 -3 is -18
x^2 - 6x -15 = 3
x^2 - 6x -15- 3 =
x^2 - 6x - 18 = 0
When equations equal or set equal to zero we can then use the quadratic formula found in your book.
x1
= −(−8) − √ (−8)2 − 4×1×(−18) / 2×1
= 8 − 2 × √ 34
/2
≈ −1.831
x^2
= −(−8) + √ (−8)2 − 4×1×(−18)
/2×1
= 8 + 2 × √ 34 / 2
≈ 9.831
