The angles of a triangles are x°, 3x° and 30°. When asked to solve for x, Alvi shows the work in post-it A below. Brian shows the work in post-it B below. Who is correct and why? Why mistake did the incorrect person make? that is the pic for post it a.
the post it b said

x + 3x + 30 = 180
4x + 30 = 180
4x = 150
x = 37.5

See explanation

Step-by-step explanation:

OK.  Alvi is incorrect because he didn't add the measures of all 3 angles of the triangle, whereas Brian did.  So, Brian is correct and Alvi needs to work on that kind of problem.

infinitely many solutions

step-by-step explanation:

we have been given the equation;

2(2x + 3) = -4 + 2(2x + 5)

we need to determine the value of x.

2(2x + 3), we expand this expression to obtain 4x + 6

similarly 2(2x + 5) will become 4x + 10

now we have;

4x + 6 = -4 + 4x + 10

4x + 6 = 4x + 10 - 4

4x + 6 = 4x + 6

the expression on the left hand side is identical to the one on the right hand side. therefore, we are looking at just a single straight line whose equation is;

y = 4x + 6

consequently, we shall have infinitely many solutions