Hello from MrBillDoesMath!
Answer:
n = 5
Discussion:
Let the original number be "n" Translating the problem statement to mathematical symbolism:
n + 4 = 19 - 2n => add 2n to both sides
n + 2n + 4 = 19 - 2n + 2n => combine like terms
3n + 4 = 19 => subtract 4 from both sides
3n = 19 -4 = 15 => divide both sides by 3
n = 15/3 =5
Check: Does 5 +4 = 19 - 2(5)? Does 9 = 9? Yes. so the value for n is confirmed correct.
Thank you,
MrB
we are given
62% of the students take math
so,

49% take science

38% take both science and math
n(M∩S)=38
now, we can use union formula
n(M∪S)=n(M)+n(S) -n(M∩S)
now, we can plug values
and we get
n(M∪S)=62+49 -38
n(M∪S)=73
so,
the percentage takes at least one science or math course is 73%..........Answer
Plug in 3 for x. 5(3) (-2(3) x 2) = 15(-6 x 2) = 15(-12) = -180.
Answer:
its D (18)
Step-by-step explanation:
I counted '-'