Answer:
C.H. Weaver M.D. updated 10/2020 What is the Carcinogenicity antigen (CEA)? CEA is an antigen (small protein) that is found on the surface of many types of cancer cells and high levels of CEA can be detected in the blood of some patients with cancer and the developing fetus.
Step-by-step explanation:
Answer:
The price of one cookie is $1.25 and the price of one cake is $15.
Step-by-step explanation:
Let $x be the price of one cookie and $y be the price of one cake.
1. On Monday, Sean bought 3 cookies and 5 cakes, then he spent $(3x+5y) and this is $78.75. Thus,

2. On Tuesday, Sean bought 8 cookies and 2 cakes, then he spent $(8x+2y) and this is $40. Thus,

3. Solve the system of two equations:

Multiply the first equation by 2 and the second equation by 5 and subtract them:

Then

Answer:
-9
Step-by-step explanation:
18÷x = -2
18 = -2×x
18 = -2x
-9 = x
x = -9
X = -2
set equations equal and solve
2x+7 = -x+1
collect like terms
3x = -6
divide
x=-2