Bytelearn - cat image with glassesAI tutor

Welcome to Bytelearn!

Let’s check out your problem:

The function 
k is given by 
k(x)=3x^(2)-19 x-14. Find all values of 
x for which 
k(x) > 0.

The function k k is given by k(x)=3x219x14 k(x)=3 x^{2}-19 x-14 . Find all values of x x for which k(x)>0 k(x)>0 .

Full solution

Q. The function k k is given by k(x)=3x219x14 k(x)=3 x^{2}-19 x-14 . Find all values of x x for which k(x)>0 k(x)>0 .
  1. Factor quadratic equation: Find the roots of the quadratic equation by factoring k(x)=3x219x14k(x) = 3x^2 - 19x - 14.k(x)=(3x+1)(x14)k(x) = (3x + 1)(x - 14)Set each factor equal to zero to find the roots.3x+1=03x + 1 = 0 and x14=0x - 14 = 0
  2. Solve for roots: Solve for xx in each equation.\newlineFor 3x+1=03x + 1 = 0, x=13x = -\frac{1}{3}\newlineFor x14=0x - 14 = 0, x=14x = 14
  3. Determine intervals to test: Determine the intervals to test around the roots.\newlineWe have two intervals: x<13x < -\frac{1}{3}, 13<x<14-\frac{1}{3} < x < 14, and x>14x > 14.
  4. Choose test points: Choose test points from each interval and plug them into k(x)k(x). For x<13x < -\frac{1}{3}, use x=1x = -1. For 13<x<14-\frac{1}{3} < x < 14, use x=0x = 0. For x>14x > 14, use x=15x = 15.
  5. Evaluate k(x)k(x): Evaluate k(x)k(x) at each test point.\newlinek(1)=3(1)219(1)14=3+1914=8k(-1) = 3(-1)^2 - 19(-1) - 14 = 3 + 19 - 14 = 8\newlinek(0)=3(0)219(0)14=14k(0) = 3(0)^2 - 19(0) - 14 = -14\newlinek(15)=3(15)219(15)14=67528514=376k(15) = 3(15)^2 - 19(15) - 14 = 675 - 285 - 14 = 376
  6. Determine where k(x)>0k(x) > 0: Determine where k(x)k(x) is greater than 00 based on the test points.\newlinek(x)>0k(x) > 0 when x<13x < -\frac{1}{3} and when x>14x > 14.

More problems from Domain and range of quadratic functions: equations