Answer:
13
Step-by-step explanation:
In order to find the answer, plug in 4 for x.

Answer:
y = 2x - 4; Alex is 18.
Step-by-step explanation:
Since Alex is 4 years younger than 2 times his sister's age, and his sister is y and Alex is x, the function of y to x must be y = 2x - 4.
According to the rule, if Alex's sister is 11, Alex is 2 times that minus four. If you calculate that, you get
11 * 2 = 22
22 - 4 = 18
So Alex is 18 if his sister is 11.
Answer:
<u>77.4 degrees and 12.6 degrees</u>
Step-by-step explanation:
Let the angles be x and x - 64.8.
Therefore, on the basis of knowledge that complementary angles add up to 90 degrees :
x + x - 64.8 = 90
2x = 154.8
x = <u>77.4 degrees</u>
x - 64.8 = 77.4 - 64.8 = <u>12.6 degrees</u>
Answer:
The perpendicular line would be y = -2x - 4
Step-by-step explanation:
First we must solve the original equation for y.
x - 2y = 7
-2y = -x + 7
y = 1/2x - 7/2
In order to find the equation of this line, we first have to note that perpendicular lines have opposite and reciprocal slopes. Therefore, since the original line has a slope of 1/2, we know the new line will have a slope of -2. Now we can use that information along with the given point in point-slope form to find the equation.
y - y1 = m(x - x1)
y - 2 = -2(x + 3)
y - 2 = -2x - 6
y = -2x - 4