answer:
number 4
Step-by-step explanation:
24 ? 8×3=24
Answer: (-1,2)
Steps:
Solve by elimination
Multiply the first equation by 2 to make the coefficients of x in both equations the same
2(x+2y=3)
2x+4y=6
Then line them up and subtract
2x+y=0
-2x+4y=6
= -3y=-6
Divide both sides by -3 to isolate y
y=2
Then substitute 2 for y into one of the equations to find x.
x+2(2)=3
x+4=3
x=-1
Perpendicular lines will meet at a 90 degree angle (a right angle)...so ur answer is B
Answer:
14
Step-by-step explanation:
First, find out how many half-lives have passed. Divide the number of minutes by the length of a half-life. 34÷17=22 half-lives have passed. Now figure out how much praseodymium will be left after 2 half-lives have passed. Multiply the starting amount of praseodymium by 12 a total of 2 times. 56 x 1/2 x 1/2 = 14 That calculation could also be written with exponents:56x (1/2)^2=14 After 2 half-lives, the amount of praseodymium left will be 14 grams.