Please help.
Algebra.

4) C

5) D

Step-by-step explanation:

4) Solving by substitution means you will try to get one of the variables isolated for one of the equations (y=), then plug that in to the other equation. C is the best answer choice for a first step in isolating a variable

5) For these kinds of questions it is best to convert the equations to be in the same form (y=mx+b or Ax+By=C). You should get y=3x+5 for both equations, meaning they are the same equations, therefore infinite solutions exist

according to the triangle sum theorem, all the angles in a triangle must add up to 180 degrees. if we know one angle is already 90, we do 180-90=90. the other 2 angles must add up to 90, exactly.

step-by-step explanation:

income. 10x+1300

expenses 3x+(1800+1500)

expenses 3x+3300

to break even:

income = expense,

10x + 1300 = 3x + 3300,

solve for x.

step-by-step explanation:

mark brainliest