I really want to learn, looking forward to do so. Please help me!

x+y=7

7x+8y=67

9x+21=4y

Thank you for the opportunity to help you with your question!

In order to do these problems, you want to write them in standard form.

Standard form always looks like y= kx+b (where k is some number and b is some constant).

1. x+y=7 **Notice the y is in the correct place, and the 7 is in the correct place. Only the x is incorrect.

So, we must subtract x to both sides

x-x+y=-x+7

y=-x+7.

2.

7x+8y=67 **Notice the 67 is on the right side, but the 7x is not. Also, the coefficient to y is not 1**

First subtract 7x to both sides.

7x-7x+8y=-7x+67

8y=-7x+67

Divide by negative 8 to both sides to make the coefficient 1 in front of the y

y=-7/8 x+67/8

3.

9x+21=4y **the only issue with this problem is the coefficient of 4 in front of the y**

Divide by four

y=9/4x+21/4

For problem 2, I meant to say divide by 8 **NOT** by negative 8.

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