Answer: The answer is (B) 2x + 3(3x – 5) = 51
.
Step-by-step explanation: We are given three options and we are to select which choice shows the result of substituting 3x – 5 into the second equation for y.
So, y = 3x - 5.
Since the standard form of a linear equation i two variables is ax + by = c, so the second equation as given in the options must be of the form 2x + 3y = 51.
If we substitute y = 3x - 5, then this equation becomes
2x + 3(3x - 5) = 51.
Thus, (B) 2x + 3(3x – 5) = 51 is the correct option.
3x + 6 = 48 (alternate angles are equal)
- 6
3x. = 42
÷3
x = 14 degrees
180-48 - 2y + 5y-9 =180
123 + 3y = 180
-123
3y = 57
÷3
y = 19 degrees
Explanation:
To find the last angle on the top straight line, do:
180 - (the 2 given angles).
So, 180 - (3x + 16, which is 48 due to alternate angles being equal). Then, minus the 2y.
(180 - 48 - 2y) & simplify => 132 - 2y
This gives you the equation for the missing angle on our top straight line.
Thus, co-interior angles add to 180. So, we add the new equation (132 - 2y) to 5y - 9.
Simplify
=> 123 + 3y (because - 2+5 =3)
and put it equal to 180. Solve for y
Hope this helps!
