Substitution is where we first Isolate one of the unknowns, express it in terms of the other unknown, and replace the isolated unknown with the other unknown in another equation. So that each time we only need to deal with one unknown. I think you'll get a better idea here:
First name these 2 equations with 1 and 2.
4x + 5y = 7 (1)
y = 3x + 9 (2)
Since y is already isolated in (2), so we can skip the isolation step and continue to substitute.
Substitute (2) into (1).
4x + 5(3x+9) = 7
Expand.
4x + 15x + 45 = 7
Group.
19x + 45 = 7
Shift +45 to the other side and turn it into -45.
19x = 7 - 45
19x = -38
Shift x19 to the other side, turn it into /19.
X = - 38/19
X = - 2
Now we solved x already, we can just substitute x= - 2 back to equation (2).
y = 3(-2) + 9
y = - 6 + 9
y = 3
So, the answers are
x = - 2
y = 3
2.5 4/5 8% that is an example of written fractions decimal and percents
Answer:
The perimeter and area of the square are 56 units and 196 square units, respectively.
Step-by-step explanation:
The inner right triangle represents a 45-45-90 right triangle, which has the feature of a hypotenuse whose length is 
time the length of any of its legs. If the hypotenuse has a measure of 
, then the legs of the triangle have a measure of 
.
Now, we are aware that the side length of the square is twice the length of the leg of the right triangle. Then, side length of the square is 14 units long.
Lastly, we know from Geometry that the perimeter and area of the square are represented by the following expressions:
Perimeter
(1)
Area
(2)
Where 
is the side length of the square.
If we know that 
, then the perimeter and area of the square are, respectively:
The perimeter and area of the square are 56 units and 196 square units, respectively.
Answer:
84
Step-by-step explanation:
Brainliest please?
