If 3a + 2b = 7 and 2a + 2b = 9 , what is the value of
1 answer:
Hey there :)
We have two equations:
3a + 2b = 7
2a + 2b = 9
We need to solve simultaneously to find the values of a and b
eq.1 3a + 2b = 7
eq.2 ( 2a + 2b = 9 ) x -1 ) multiply by -1 to cancel 2b
3a + 2b = 7
- 2a - 2b = -9 ( Add both together )
-------------------
a = - 2
Substitute the value you found for a in a in order to find b
3( - 2 ) + 2b = 7 2( - 2 ) + 2b = 9
- 6 + 2b = 7 OR - 4 + 2b = 9
2b = 13 2b = 13
b =
b =
We have two equations:
3a + 2b = 7
2a + 2b = 9
We need to solve simultaneously to find the values of a and b
eq.1 3a + 2b = 7
eq.2 ( 2a + 2b = 9 ) x -1 ) multiply by -1 to cancel 2b
3a + 2b = 7
- 2a - 2b = -9 ( Add both together )
-------------------
a = - 2
Substitute the value you found for a in a in order to find b
3( - 2 ) + 2b = 7 2( - 2 ) + 2b = 9
- 6 + 2b = 7 OR - 4 + 2b = 9
2b = 13 2b = 13
b =
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What your teacher wants is for you to isolate y in the given equation. In other words, get y all by itself.
To do this, you'll do two basic steps:
Step 1) Subtract 2x from both sides
Step 2) Divide both sides by 3
Let's do that and we get...
2x+3y = 1470
2x+3y-2x = 1470-2x ... apply step 1
3y = 1470-2x
3y = -2x+1470
3y/3 = (-2x+1470)/3 ... apply step 2
y = (-2x)/3 + 1470/3
y = (-2/3)x + 490
After isolating y, we get y = (-2/3)x + 490
To get this into function notation, we simply replace y with f(x) to get the final answer f(x) = (-2/3)x+490 which is the same as writing
This graph represents all of the ordered pairs (x,y) that make the original equation true. For example, the point (x,y) = (0,490) is on the line where x = 0 and y = 490. This point is when 0 sandwiches are sold and 490 wraps are sold yielding a profit of $1470. Another point on this line is (x,y) = (3,488). Now 3 sandwiches have been sold along with 488 wraps leading to the same profit of $1470. Any ordered pair point you pick on the line should lead you to the same profit.
To do this, you'll do two basic steps:
Step 1) Subtract 2x from both sides
Step 2) Divide both sides by 3
Let's do that and we get...
2x+3y = 1470
2x+3y-2x = 1470-2x ... apply step 1
3y = 1470-2x
3y = -2x+1470
3y/3 = (-2x+1470)/3 ... apply step 2
y = (-2x)/3 + 1470/3
y = (-2/3)x + 490
After isolating y, we get y = (-2/3)x + 490
To get this into function notation, we simply replace y with f(x) to get the final answer f(x) = (-2/3)x+490 which is the same as writing
This graph represents all of the ordered pairs (x,y) that make the original equation true. For example, the point (x,y) = (0,490) is on the line where x = 0 and y = 490. This point is when 0 sandwiches are sold and 490 wraps are sold yielding a profit of $1470. Another point on this line is (x,y) = (3,488). Now 3 sandwiches have been sold along with 488 wraps leading to the same profit of $1470. Any ordered pair point you pick on the line should lead you to the same profit.