# How do you solve the equation #4x^2-7x-15=0# by graphing?

##### 1 Answer

#### Explanation:

Given:

Solve means find the

Graph the function:

graph{4x^2 - 7x - 15 [-10, 10, -20, 10]}

On a TI 83, 83+, 84, 84+, to **find the first zero** , you would use:

**2nd Calc 2** . zero **ENTER**

The calculator asks: Left Bound?

You **move the cursor** using the arrow keys until you are to the left and above the **ENTER**

The calculator asks: Right Bound?

You **move the cursor** using the arrow keys until you are to the right and below the **ENTER**

The calculator asks: Guess?

You can just press **ENTER** unless there are two zeros really close to each other. Then you would need to move the cursor closer to the one you want.

Calculator says: Zero X = -1.25 Y = 0

**To find the 2nd zero:**

**2nd Calc 2** . zero **ENTER**

You **move the cursor** using the arrow keys until you are to the left and below the **ENTER**

The calculator asks: Right Bound?

You **move the cursor** using the arrow keys until you are to the right and above the **ENTER**

The calculator asks: Guess?

You can just press **ENTER** unless there are two zeros really close to each other. Then you would need to move the cursor closer to the one you want.

Calculator says: Zero X = 3 Y = 0