For options A– E choose all of the expressions that are equivalent to 3(4x + 3).
1 answer:
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Answer:
x = -2; y = 3
Step-by-step explanation:
5x + 4y = 2 (1)
3x + 3y = 3 (2)
Multiply (1) by 3 and (2) by 4
15x + 12y = 6 (3)
12x + 12y = 12 (4)
Subtract (4) from (3)
15x - 12x = 6 - 12
3x = -6
x = -6/3
x = -2
Substitute x = -2 into (1)
5x + 4y = 2
5(-2) + 4y = 2
-10 + 4y = 2
4y = 2 +10
4y = 12
y = 12/4
y = 3
The first error is when he multiplied equation (2) by 4
He didn't multiply the right hand side of the equation by 4
3x + 3y = 3 ×4
12x + 12y = 12
But he wrote
12x + 12y = 3
The the next error is subtracting the left hand side of the equation and adding the right hand side
15x + 12y = 6
12x + 12y = 3
He wrote
3x = 9
Instead of 3x = 3
Answer:
A. (1, -2)
Step-by-step explanation:
We can substitute the variables of x and y into the inequality of .
Let's start with A, -2 being y and 1 being x.
The absolute value of 1 is 1, and negating that gets us -1.
Indeed, -2 is less than -1! So A is a solution to the inequality.
Let's test the rest of them, just in case.
For B:
Absolute value of 1 is 1, negating it is -1.
-1 is EQUAL to -1, not less than it, so is not a solution to the inequality.
Let's try C.
Absolute value of 1 is 1, negating it is -1.
0 is GREATER than -1, so that is not a solution to the inequality.
Hope this helped!