Answer:
x = 40
Step-by-step explanation:
The three angles in a triangle add to 180 degrees
x + 30 + (3x-10) = 180
Combine like terms
4x +20 = 180
Subtract 20 from each side
4x+20-20 = 180-20
4x= 160
Divide each side by 4
4x/4 =160/4
x = 40
A = 11, b = 7
You just needed to multiply the terms together
21) 3(2j-k)=108 It is asking you to set the equation equal to j
distribute the 3
6j-3k=108
move k to the other side by adding on both sides
6j=108+3k
divide everything by 6
j=18+0.5k