Answer: A
Step-by-step explanation:
2x²-2x-9=0
this is a quadratic equation so we will use the quadratic formula .
Δ= b²-4*a*c
let's calculate Δ to khow how many solutions this equations have .
Δ= (-2)²-4*2*(-9)
= 76
we notice that 76>0
so this equation has two solutions : (-b-√76)/4 and (-b+√76)/4
- let's calculte the values :
- (-b-√76)/4=
(-b+√76)/4=
the trick here is to notice that :
= 
= 
= 2
Now we will simplify Δ by factoring by 2
= 
so the answer is a .
Answer:
(x-3)(x+3)
Step-by-step explanation:
that's what it factors to
Answer:
Graph a
Step-by-step explanation:
Answer:The obvious difference between substitution and elimination reactions is that substitution reactions replace one substituent with another while elimination reactions simply remove the substituent. ... The major difference between the groups is the number of steps the reaction takes place over.
Step-by-step explanation:
Answer:
Cheryl is correct.
Step-by-step explanation:
Cheryl solved a problem : 84 ÷ 0.01 = 8,400.
This is absolutely right.
When we divide any whole number with the divisor having decimal, we change the divisor to a whole number before performing the division.
To do this, we multiply both the numbers (divisor and dividend) by the same power of 10, until the divisor is a whole number.
= 
to make divisor a whole number we will again multiply both the numbers by 10.
= 
= 8,400
Now answer would be 8400.
Therefore, Cheryl is correct.
