Hot Student Stories

# Which of the following is an extraneous solution of mc015-1.jpg? x = –12 x = –3 x = 3 x = 12

#### 1 answer

### Add you answer

##### Wanna comment?

Please Sign In / Sign Up

The answerthe complete the question is as follows:which of the following is an extraneous solution of (45 - 3x)^1/2 =x -9for the resolution of an equation, this is the method:find the square of the value of each member of the equation[(45 - 3x)^1/2 ]2 = (x -9)2 (E)to expand each value of the member[(45 - 3x)^1/2 ]2 = 45 - 3x, because (sqrt (a )2 = the condition is 45 - 3x≥0 ( because of the square root)means - 3x≥ -45 and x ≤ 15(x -9)2 = x2-18x + 81so 45 - 3x = x2-18x + 81, this is equivalent to x2 - 15x +36 =0this equation you must solve for x, to find the helpDelta = 152 - 4*36 = 81, so x = - (-15) - sqrt (81) / 2 *1=15-9 /2= 3 and x = - (-15) +sqrt (81) / 2 *1= 15 +9/2= 24/2=12for x= 12, the equation given above ( equation (E) has no solution, because we can find 3=9so a strange solution is x = 12