How many times does the graph of 4x = 32 - x2 cross the x-axis ?
2 answers:
Answer:
Step-by-step explanation:
● 4x = 32 - x^2
Add x^2 to both sides
● 4x +x^2 = 32 -x^2+x^2
● x^2 +4x = 32
Substract 32 from both sides
● x^2+4x -32 =32-32
● x^2 +4x-32=0
That is a quadratic equation
We will use the determinant method
The determinant is b^2-4ac
● a = 1
● b = 4
● c = 32
● b^2-4ac = 4^2 -4×1×(-32) = 144
144 is positive so the parabola will cross the x-axis two times
● x = (-b -/+ √(b^2-4ac))/2a
● x = (-4 +/- 12) /2
● x = 8/2 or x= -16/2
● x = 4 or x =-8
The solutions are 4 and -8
You might be interested in
The total of 42 swimmers are competing
Step-by-step explanation:
The given is:
- The ratio of runners to swimmers was 3 : 2
- When 28 runners dropped out of the competition, the ratio became 5 : 6
We need to find how many total swimmers are competing
∵ The ratio of runners to swimmers was 3 : 2
- Multiply each term of the ratio by x
∴ There are 3x runners and 2x swimmers
∵ 28 runners dropped out of the competition
∴ The number of runners who complete = 3x - 28
∵ The ratio became 5 : 6
- Equate the ratio between the new number of runners and the
number of swimmers by 5 : 6
∵ The new number of runners = 3x - 28
∵ The number of swimmers = 2x
∴
- By using cross multiplication
∴ 6(3x - 28) = 5(2x)
- Simplify both sides
∴ 18x - 168 = 10x
- Add 168 to both sides
∴ 18x = 10x + 168
- Subtract 10x from both sides
∴ 8x = 168
- Divide both sides by 8
∴ x = 21
∵ The number of swimmers is 2x
∵ x = 21
∴ The number of swimmers = 2(21) = 42
The total of 42 swimmers are competing
Learn more:
You can learn more about the ratio in brainly.com/question/2707032
#LearnwithBrainly