How do you solve 2x+y=5 and x-y=1 by substitution

[120 total points] (public health) in one of the largest human experiments ever conducted, in 1954 a randomized controlled trial was run to see whether a vaccine developed by a doctor named jonas salk was effective in preventing paralytic polio. a total of 401,974 children (ages 6–9), chosen to be representative of those who might be susceptible to the disease, were randomized to two groups: 200,745 children (the control group c) were injected with a harmless saline solution (a placebo) and the other 201,229 children (the treatment group t) were injected with salk’s vaccine.what was the point of giving saline solution to the children who didn’t get the vaccine? explain briefly.

Which safe and legal options do teen parents have if they think they are not ready to be parents? check all that apply. leave the baby in front of someone's door. surrender the baby under their state’s safe-haven laws. place the baby for adoption. release custody to the baby’s grandparents. give the baby to a stranger.

Which feelings are examples of emotional needs? choose exactly 2 answers that are correct. a.love b.belonging c.joy d.anger