Answer:
Option A is correct, i.e. x = -3, x = 7.
Step-by-step explanation:
Given the equation is x² -4x -21 = 0.
We can compare it with general quadratic equation i.e. ax² +bx +c =0.
then a = 1, b = -4, c = -21.
We can use Quadratic formula as follows:-
x = ( -b ± √(b²-4ac) )/2a
x = ( +4 ± √(16-4*1*-21) )/2*1
x = ( +4 ± √(16+84) )/2
x = ( +4 ± √(100) )/2
x = ( +4 ± 10 )/2
x = (4+10)/2 or x = (4-10)/2
x = 14/2 or x = -6/2
x = 7 or x = -3
Hence, option A is correct, i.e. x = -3, x = 7.
Answer:
n² + 5 = 41 n = 6
Step-by-step explanation:
n² + 5 = 41
n² + 5 - 5 = 41 - 5
n² = 36
What squared equals 36? 6!
6² = 6 * 6 = 36
Check your answer!
6² + 5 = 41
36 + 5 = 41
41 = 41
Have a good night! :)
Answer:
B) 
Step-by-step explanation:
2(x + 12) − 16 ≤ 8
I am joyous to assist you anytime.
If x=2.5, then 5x would equal 5*2.5, or 12.5
