The correct answer is -29.7
Answer:
28.3 that's the answer
Step-by-step explanation:
Theorem of cosine:
a²=b²+c²-2bc(cos α) ⇒cos α=-(a²-b²-c²) / 2bc
In this case:
a=15 cm
b=10 cm
c=5 cm
cos α=-(15²-10²-5²) / 2*10*5
cos α=-100 / 100
cos α=-1
A=arc cos -1=180º This is impossible, because:
A+B+C=180º; then B=C=0º This is impossible for make a triangle (B>0 and C>0 if we want to make a triangle).
Therefore: it is not possible can make a triangle with side lengths of 5 cm, 10 cm and 15 cm.
I hope this helps you
2x^2-4x+7=0 a=2 b=-4 c= 7
disctirminant =b^2-4ac
disctirminant =(-4)^2-4.2.7
disctirminant = 16-56= -40
x=-b+square root of disctirminant ÷2a
x=4+2square root of (-10)/4
x=2+square root of (-10)/2
x'=4 -2 square root of (-10)/4
x'=2 -square root of (-10)/2
#6
x^2 = 1
x = - 1 and x = + 1
#7
a^2 + 1 = 19
a^2 =18
a^2 =√ 9 <span>√ 2
a = + 3</span>√ 2 and a = - 3<span>√ 2</span>
