Answer:
Given the system of equation:
......[1]
......[2]
we can rewrite equation [2] as;
......[3]
Substitute equation [3] into [1] to eliminate x, and solve for y;

Using distributive property: 

Combine like terms;
16 - 8y = -4
Add 4 to both sides we have;
20 - 8y = 0
Add 8y to both sides we have;
20 = 8y
Divide 8 to both sides we have;

Substitute the y-value in [3] we have;

x = 8 - 5 = 3
Therefore, the expression should be substituted into the first equation is,
and also the value of x = 3 and y = 2.5
Becky was trying to open the door, but it was stuck,
so she asked me to compound on it with her.
we have
f(x)
and
g(x)=-2f(x)+5
so
step 1
First transformation
Reflection about the x-axis
so
f(x) -----> -f(x)
step 2
Second transformation
A vertical dilation with a scale factor of 2
so
-f(x) ------> -2f(x)
step 3
Third transformation
A translation of 5 units up
so
-2f(x) -------> -2f(x)+5
Answer:
f(-5)=28
Step-by-step explanation:
f(x)=x²-2x-7
f(-5) means that we have to replace x by -5.
f(-5)=(-5)²-2(-5)-7=25+10-7=25+3=28
From all those aforementioned, the true statement is: Thanh’s grade is 2.5 standard deviations below the mean of the test grades.