Math Problem Statement

the line 3y = 4x - 15 intersects thje curve 8x^2-27^2 =45 at points a and b find points a and b

Solution

To find the points AA and BB where the line 3y=4x153y = 4x - 15 intersects the curve 8x227y2=458x^2 - 27y^2 = 45, we need to solve the system of equations. Let's go step by step:

Step 1: Express yy from the line equation

The equation of the line is:

3y=4x153y = 4x - 15

Solve for yy:

y=4x153y = \frac{4x - 15}{3}

Step 2: Substitute yy in the curve equation

Now substitute y=4x153y = \frac{4x - 15}{3} into the curve equation:

8x227y2=458x^2 - 27y^2 = 45

Substituting for yy:

8x227(4x153)2=458x^2 - 27\left(\frac{4x - 15}{3}\right)^2 = 45

Step 3: Simplify the equation

First, square the expression for yy:

(4x153)2=(4x15)29\left(\frac{4x - 15}{3}\right)^2 = \frac{(4x - 15)^2}{9}

So the equation becomes:

8x227(4x15)29=458x^2 - 27 \cdot \frac{(4x - 15)^2}{9} = 45

Simplify the fraction:

8x23(4x15)2=458x^2 - 3 \cdot (4x - 15)^2 = 45

Step 4: Expand (4x15)2(4x - 15)^2

Expand (4x15)2(4x - 15)^2:

(4x15)2=16x2120x+225(4x - 15)^2 = 16x^2 - 120x + 225

Substitute this into the equation:

8x23(16x2120x+225)=458x^2 - 3(16x^2 - 120x + 225) = 45

Step 5: Simplify the equation

Distribute the 3:

8x2(48x2360x+675)=458x^2 - (48x^2 - 360x + 675) = 45

Simplify further:

8x248x2+360x675=458x^2 - 48x^2 + 360x - 675 = 45

Combine like terms:

40x2+360x675=45-40x^2 + 360x - 675 = 45

Subtract 45 from both sides:

40x2+360x720=0-40x^2 + 360x - 720 = 0

Step 6: Solve the quadratic equation

Divide the equation by -40 to simplify:

x29x+18=0x^2 - 9x + 18 = 0

Now solve this quadratic equation using the quadratic formula:

x=(9)±(9)24(1)(18)2(1)x = \frac{-(-9) \pm \sqrt{(-9)^2 - 4(1)(18)}}{2(1)}

x=9±81722x = \frac{9 \pm \sqrt{81 - 72}}{2}

x=9±92x = \frac{9 \pm \sqrt{9}}{2}

x=9±32x = \frac{9 \pm 3}{2}

So the two solutions for xx are:

x=9+32=6orx=932=3x = \frac{9 + 3}{2} = 6 \quad \text{or} \quad x = \frac{9 - 3}{2} = 3

Step 7: Find the corresponding yy values

Now substitute these values of xx into the equation for y=4x153y = \frac{4x - 15}{3}:

  • For x=6x = 6:

y=4(6)153=24153=93=3y = \frac{4(6) - 15}{3} = \frac{24 - 15}{3} = \frac{9}{3} = 3

  • For x=3x = 3:

y=4(3)153=12153=33=1y = \frac{4(3) - 15}{3} = \frac{12 - 15}{3} = \frac{-3}{3} = -1

Step 8: Conclusion

The points of intersection are:

A(6,3)andB(3,1)A(6, 3) \quad \text{and} \quad B(3, -1)

Would you like any further explanation or more details?

Here are 5 related questions for further practice:

  1. How do you solve systems of equations with a line and a circle?
  2. Can you find the distance between points A(6,3)A(6, 3) and B(3,1)B(3, -1)?
  3. What happens if the line does not intersect the curve?
  4. How do you solve a system with a line and a parabola?
  5. How does the discriminant help determine the nature of the roots in quadratic equations?

Tip: For quadratic equations, always check the discriminant (b24acb^2 - 4ac) to determine whether the equation has real, imaginary, or repeated roots.

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Math Problem Analysis

Mathematical Concepts

Algebra
Systems of Equations
Quadratic Equations

Formulas

Line equation: y = mx + c
Quadratic formula: x = (-b ± √(b² - 4ac)) / 2a

Theorems

Quadratic formula
Properties of Parabolas and Hyperbolas

Suitable Grade Level

Grades 10-12