Answer:
2x2+9x−1=x
Step 1: Subtract x from both sides.
2x2+9x−1−x=x−x
2x2+8x−1=0
Step 2: Use quadratic formula with a=2, b=8, c=-1.
x=
−b±√b2−4ac
2a
x=
−(8)±√(8)2−4(2)(−1)
2(2)
x=
−8±√72
4
x=−2+
3
2
√2 or x=−2+
−3
2
√2
Step-by-step explanation:
This is what I got but I'm not 100% positive. I checked it on a calculator and it seemed to check out.
Answer:
84
Step-by-step explanation:
let a be the 1's digit and b the 10's digit, then
a = 2b ← twice the 10's digit, thus
sum = 2b + b = 12, that is
3b = 12 ( divide both sides by 3 )
b = 4
and a = 2b = 2 × 4 = 8
The 2 digit number is 84
Combine like terms to get
