What is the discriminant of x^2-8x+7=0
1 answer:
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Answer: 9. x=-3/2 10. x=2
x= 5/2 x=5/3
Step-by-step explanation:
9. Factor the equation:
How: put 4x^2 in the bottom left box and -15 in the upper right box.
then multiply 4x^2 x -15 = -60x^2 and put your answer in the top center box of the diamond.
Put the -4x from the equation in the bottom box. Then list out factors that multiply to the top box (-60x^2) and add to the bottom box (-4x) The two factors are -10 and 6
-10 x 6 = -60
-10 + 6 = -4
Put -12x and -5x in the remaining white boxes and find what numbers multiply to each.
I attached a picture. The colored dots correspond with each other.
Eg: Orange dot x orange dot = number in white square
Now you get the two factors (2x+3)(2x-5)
Set both of these equal to 0 and solve
0=2x+3 0=2x-5
x= -3/2 x= 5/2
Do the same for the other problem
Answer:
The correct answer is t < 60.
Step-by-step explanation:
Lauren wants to keep her cell phone bill below $60 per month.
Lauren's current cellphone plan charges her a fixed price of $30 and per text price for one text is $0.50.
Let Lauren sends t texts in a complete month.
Total money spent on texts in a month is given by $ (0.50 × t)
Therefore Lauren's total spent in a month is given by $ (30 + (0.50 × t)).
But this amount should be under $60 as per as the given problem.
∴ 30 + (0.50 × t) < 60
⇒ (0.50 × t) < 30
⇒ t <
⇒ t < 60.
So in order to keep her phone monthly bill under $60, Lauren should keep her number of texts below 60.