Answer:
-5
Step-by-step explanation:
Substituting x=4 into the equation gives a 2-step linear equation in y. It is solved by isolating the variable and making its coefficient be 1.
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<h3>use x=4</h3>
When x=4, the equation becomes ...
-3x +9y = -57
-3(4) +9y = -57
-12 +9y = -57
<h3>solve 2-step equation</h3>
The <u>first step</u> is to "isolate" the variable term (9y) by adding the opposite of the constant that is on the same side of the equation. The result is that the variable term is by itself on one side of the equal sign.
-12 +12 +9y = -57 +12 . . . . . add the opposite of -12
9y = -45 . . . . . . . . . . . . . . simplify
The <u>second step</u> is to make the coefficient of y be 1. We do that by multiplying by its inverse, 1/9. Equivalently, we divide by 9.
(1/9)(9y) = (1/9)(-45) . . . . multiply by the inverse of 9
y = -5 . . . . . . simplify
Line1: y = -x + 2
Line2: y = 2x - 1
Solution: (1,1)
Answer:
6a−14
Step-by-step explanation:
Answer:
18
Step-by-step explanation:
The interior and exterior angle of a polygon is supplementary
let interior be I
let exterior be E
I + E = 180
Since the interior angle is 8 times that of an exterior angle,
8E + E = 180 [replacing I with 8E]
9E = 180
E = 20
The exterior angle is 20 degrees
I + E = 180
I + 20 = 180
I = 160
The interior angle is 160 degrees.
The equation to find the interior angle of a polygon with 'n' number of sides is:
I = ( (n − 2) × 180 ) ⁄ n
We know the interior angle, so plug it in and solve for n:
160 = ( (n − 2) × 180 ) ⁄ n
160n = (n − 2) × 180
160n = 180n − 360
-20n = -360
n = 18
