find where they intercept eachother then check points on either sides of the intercepts to find where the statement â(2x+14) > x+3 holds true.
to find where they intersect make them equal to eachother.
â(2x+14) = x+3
2x + 14 = (x+3)^2
2x + 14 = x^2 + 6x + 9
0 = x^2 + 4x - 5
0 = (x + 5)(x - 1)
x = -5, x = 1
check for extraneous solutions by substituting x= -5 and x = 1 into the equation â(2x+14) = x+3
â(2(-5)+14) = -5+3
2 = -2 this is not true therefore x = -5 is not a solution
â(2(1)+14) = 1+3
4 = 4 this is true therefore x = 1 is a solution.
so now we know they intercept when x = 1
now just test a point on either side of x = 1 to find where â(2x+14) > x+3 is true
we have infact already checked x = -5 when we were checking for extraneous solution. so for values to the left of x = 1 the statement â(2x+14) > x+3 holds true. if you test a point to the right of x = 1 you will find that the statement is not true.
so we know x < 1
but there is also a lower limit to x because we cant take square root of a negative number.
However, the squaring introduced a spurious solution to â(2x+14) = x+3
When -7 < x ⤠-5 the left side is positive but the right side is negative in the original inequality. When x = -7 the left side is 0 and the right is negative.
When x < -7 you will be taking the square root of a negative number. Therefore the solution is,
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Verified answer
√(2x+14) > x+3
[√(2x + 14)]^2 > (x + 3)^2
2x + 14 > x^2 + 6x + 9
x^2 + 4x - 5 < 0
(x + 5)(x - 1) < 0
-5 < x < 1
But the domain is:
(2x + 14) ≥ 0
2x ≥ -14
x ≥ -7
So combining the two case we get:
-7 ≤ x < 1
find where they intercept eachother then check points on either sides of the intercepts to find where the statement â(2x+14) > x+3 holds true.
to find where they intersect make them equal to eachother.
â(2x+14) = x+3
2x + 14 = (x+3)^2
2x + 14 = x^2 + 6x + 9
0 = x^2 + 4x - 5
0 = (x + 5)(x - 1)
x = -5, x = 1
check for extraneous solutions by substituting x= -5 and x = 1 into the equation â(2x+14) = x+3
â(2(-5)+14) = -5+3
2 = -2 this is not true therefore x = -5 is not a solution
â(2(1)+14) = 1+3
4 = 4 this is true therefore x = 1 is a solution.
so now we know they intercept when x = 1
now just test a point on either side of x = 1 to find where â(2x+14) > x+3 is true
we have infact already checked x = -5 when we were checking for extraneous solution. so for values to the left of x = 1 the statement â(2x+14) > x+3 holds true. if you test a point to the right of x = 1 you will find that the statement is not true.
so we know x < 1
but there is also a lower limit to x because we cant take square root of a negative number.
â(2x+14) = 0
2x + 14 = 0
2x = -14
x = -7
so the final answer is
-7 ⤠x < 1
Square both sides,
2x + 14 > (x + 3)²
2x + 14 > x² + 6x + 9
x² + 4x - 5 < 0
Now factor,
(x - 1)(x + 5) < 0
-5 < x < 1
However, the squaring introduced a spurious solution to â(2x+14) = x+3
When -7 < x ⤠-5 the left side is positive but the right side is negative in the original inequality. When x = -7 the left side is 0 and the right is negative.
When x < -7 you will be taking the square root of a negative number. Therefore the solution is,
-7 ⤠x < 1
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