9514 1404 393
Answer:
see below
Step-by-step explanation:
It is easiest to compare the equations when they are written in the same form.
The first set can be written in slope-intercept form.
y = 2x +7
y = 2x +7 . . . . add 2x
These equations are <em>identical</em>, so have infinitely many solutions.
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The second set can be written in standard form.
y +4x = -5
y +4x = -10
These equations <em>differ only in their constant</em>, so have no solutions.
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The third set is already written in slope-intercept form. The equations have <em>different slopes</em>, so have exactly one solution.
Answer: Points (-1 , 7.5), (0 , 6), and (1 , 4.5).
Step-by-step explanation:
Step-by-step explanation:

( vertically opposite angles)



Since the three angles of a triangle add to give 180°
The the size of the largest angle 4 = 180° ×

= 180° ×
∴ the size of the largest angle = 80°
Solve for one of the variables in the first equation (in this case, I will solve for X):
X = Y + 3
Then use that value of X in the second equation to solve for Y:
X + 3Y = 9
(Y + 3) + 3Y = 9
4Y + 3 = 9
4Y = 6
Y = 1.5
Use the value of Y we just found in the X equation we created:
X = Y + 3
X = 1.5 + 3
X = 4.5
Therefore X = 4.5 or 9/2 and Y = 1.5 or 3/2.