What is -x^2+4x+21>= 0 ?

The solution to -x^2+4x+21>= 0 is -3<= x<= 7

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-x^2+4x+21>= 0

- x^{2} + 4 x + 21 \geq 0

- 3 \leq x \leq 7

Interval Notation

[- 3, 7]

Solution steps

- x^{2} + 4 x + 21 \geq 0

Factor

- x^{2} + 4 x + 21 : - (x + 3) (x - 7)

- (x + 3) (x - 7) \geq 0

Multiply both sides by

- 1

(reverse the inequality)

(- (x + 3) (x - 7)) (- 1) \leq 0 \cdot (- 1)

Simplify

(x + 3) (x - 7) \leq 0

Identify the intervals

- 3 \leq x \leq 7

19 - 2 k = 3 k - 1

3 (- \frac{41}{33}) + 7 (- \frac{2}{11}) = x

0.92 = x \cdot 2 x

4 x^{2} + 6 x = 1

- 92