Answer:
√7 ≈ 2.646
Step-by-step explanation:
The law of cosines is applicable. It tells you ...
c² = a² + b² - 2ab·cos(C) . . . . . where a, b, c are triangle side lengths, and angle C is opposite side c.
Filling in the given information, you have ...
c² = 2² + 3² - 2·2·3·cos(60°) = 4 + 9 - 12·(1/2) = 7
c = √7 ≈ 2.646
The length of the third side is √7, about 2.646 units.
Cross Multiply by 'x - 5'
Hence
y(x - 5) = 4 -3x
xy - 5y = 4 - 3x
Move all the terms containing an 'x' to one side of the equals and all the others to the opposite side.
xy + 3x = 4 + 5y
Factor out 'x'
x(y + 3) = 4 + 5y
'Cross' divide by 'y + 3'
x = ( 4 + 5y) / (y + 3 )
'x' is now the subject.
Answer:
EF=6
Step-by-step explanation:
E is the midpoint, so DE = EF
DE = 15-3x
EF = x+ 3
Since DE = EF,
15 - 3x = x + 3
-4x = -12
x = 3
If x = 3,
DE = 15 - 3*3, 15 - 9 = 6
EF = x+ 3, so EF = 3 + 3 = 6