To make the problem less complicated is the reason to add tens.
Answer:

Step-by-step explanation:


We'll substitute y into the equation:

Switch sides:

Add 2 to both sides


Divide both sides by -3:


Therefore, the value of x/solution is -3
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Answer:
a. 20
Step-by-step explanation:
just multiply 5 and $4 by 4
Answer:
m = 3, c = 0
Step-by-step explanation:
The equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
y = 3x , or y = 3x + 0 ← is in slope- intercept form
with m = 3 and c = 0