Math Problem Statement

Given that b=(2−9),c=(1x), a=7b+7c and the magnitude of a is 3577−−−−√, find x.

Solution

We are given the following information:

  • b=(29)b = (2 - 9)
  • c=(1x)c = (1x)
  • a=7b+7ca = 7b + 7c
  • The magnitude of aa is 3577\sqrt{3577}

Step 1: Compute 7b+7c7b + 7c

First, multiply both bb and cc by 7: 7b=7(29)=(1463)7b = 7(2 - 9) = (14 - 63) 7c=7(1x)=(7x)7c = 7(1x) = (7x)

Thus, aa is: a=(1463)+(7x)=(14+7,63+7x)a = (14 - 63) + (7x) = (14 + 7, -63 + 7x) a=(21,7x63)a = (21, 7x - 63)

Step 2: Find the magnitude of aa

The magnitude of aa is given by: a=(21)2+(7x63)2|a| = \sqrt{(21)^2 + (7x - 63)^2} We are also told that the magnitude of aa is 3577\sqrt{3577}. Therefore: (21)2+(7x63)2=3577\sqrt{(21)^2 + (7x - 63)^2} = \sqrt{3577}

Square both sides to eliminate the square roots: (21)2+(7x63)2=3577(21)^2 + (7x - 63)^2 = 3577 441+(7x63)2=3577441 + (7x - 63)^2 = 3577 (7x63)2=3577441(7x - 63)^2 = 3577 - 441 (7x63)2=3136(7x - 63)^2 = 3136

Step 3: Solve for xx

Take the square root of both sides: 7x63=±31367x - 63 = \pm \sqrt{3136} 7x63=±567x - 63 = \pm 56

Now, solve for xx:

Case 1: 7x63=567x - 63 = 56

7x=56+637x = 56 + 63 7x=1197x = 119 x=1197=17x = \frac{119}{7} = 17

Case 2: 7x63=567x - 63 = -56

7x=56+637x = -56 + 63 7x=77x = 7 x=77=1x = \frac{7}{7} = 1

Conclusion:

The possible values of xx are x=17x = 17 and x=1x = 1.

Would you like further details or clarifications?

Here are 5 related questions you might find interesting:

  1. How can you interpret the direction of vector aa geometrically?
  2. What happens if the magnitude of aa is changed to a different value?
  3. How would the solution change if bb and cc were in three dimensions?
  4. Can you derive a general formula for vectors of this type?
  5. What if the components of bb and cc were parametric functions of time?

Tip: Always double-check your calculations when working with square roots and solving quadratic equations.

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Math Problem Analysis

Mathematical Concepts

Vector Algebra
Magnitude of a Vector
Quadratic Equations

Formulas

Magnitude of a vector |a| = sqrt(a_x^2 + a_y^2)
Quadratic equation formula ax^2 + bx + c = 0

Theorems

Pythagorean Theorem
Quadratic Formula

Suitable Grade Level

Grades 10-12