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
Answer:
C) 60
Step-by-step explanation:
180 - 120
Answer:
C. 390 Cubic units
5 * 6 * 13 = 390 cubic units
Answer:
24
Step-by-step explanation:
How do we know that a circle must complete up to 180, then we have to:
180 - 48 = 132
Now knowing this distance we can also know the other, starting from the same concept, in addition to what the circle below is like, a semicircle refers to so we divide by 2:
(180-132) / 2 = 24
Therefore the answer is 24.
We can also do it ABC is half of ADC. So ABC = 48/2 = 24
