You add two equations together to eliminate a variable. This particular problem is nice, because it's already setup to eliminate X.
3x - 4y = 9
<span>-3x + 2y = 9
</span>
When we add these two together, 3x - 3x cancels each other out, leaving us with 0x, or nothing.
We continue with -4y + 2y (leaves us with -2y) and 9+9 (18).
-2y = 18
18/-2 = -9.
Now we have y = -9, and we can go back into the problems to solve for x.
<span>3x - 4(-9) = 9
</span>
3x + 36 = 9.
3x = -27
x = -9.
Confirm with the final equation:
-3(-9) + 2(-9) = 9
27 - 18 = 9
9 = 9 --- Confirmed.
The answer is C.
Hope this helps
<h2>
Answer:</h2>
cos 28°cos 62°– sin 28°sin 62° = 0
<h2>
Step-by-step explanation:</h2>
From one of the trigonometric identities stated as follows;
<em>cos(A+B) = cosAcosB - sinAsinB -----------------(i)</em>
We can apply such identity to solve the given expression.
<em>Given:</em>
cos 28°cos 62°– sin 28°sin 62°
<em>Comparing the given expression with the right hand side of equation (i), we see that;</em>
A = 28°
B = 62°
<em>∴ Substitute these values into equation (i) to have;</em>
<em>⇒ cos(28°+62°) = cos28°cos62° - sin28°sin62°</em>
<em />
<em>Solve the left hand side.</em>
<em>⇒ cos(90°) = cos28°cos62° - sin28°sin62°</em>
⇒ 0 = <em>cos28°cos62° - sin28°sin62° (since cos 90° = 0)</em>
<em />
<em>Therefore, </em>
<em>cos28°cos62° - sin28°sin62° = 0</em>
<em />
<em />
Answer:
0.7 or 5/7
Step-by-step explanation:
(1 3/7) ÷ 2 =
Answer:
8 35/36
Step-by-step explanation:
1 5/12 * 6 1/3= 8 35/36
