Desmos practice

Desmos simulator

Solve

$f\left(x\right)=2x^{2}-3x+1$ . Find $f\left(4\right)$ .

Find

f\left(4\right)

\displaystyle

\displaystyle

3 guided steps

Evaluate a function

$f\left(4\right)$ asks for the output when the input is 4. Define the function, then ask Desmos to evaluate it at that input.

Define it once. Substitute accurately.

Read the full reference

Before you reach for the calculator

What does the question
need you to find?

Learn to choose a strategy

01
Name the unknown.
An input, an output, a coefficient, or a maximum? That choice tells you what to read.
02
Make the relationship visible.
Graph an equation when you are unsure. Look for crossings, intercepts, or a turning point.
03
Bring the result back to the question.
Check the coordinate, units, and allowed values. A graph can help even when algebra finishes the work.

When a graph won't help

Some questions ask what a number means

A bakery sells muffins and loaves of bread. Its sales of these items totaled 1,027.50 dollars on Saturday. The equation $3.25m + 7.40b = 1{,}027.50$ represents this situation, where $m$ is the number of muffins sold and $b$ is the number of loaves sold. According to the equation, what is the price, in dollars, of each loaf of bread?

The Desmos reference

A guide for the next question.

19 guides

Calculator skills

Start with the calculatorExpressions, graph controls, and a first equation.Find every intersectionRead the coordinates and keep both solutions.Choose a useful strategyKnow what you are looking for before you type.Tables & calculated columnsPlot pairs or let a function fill the outputs.Fit a model from a tableChoose the model, then interpret its coefficients.Fractions ↔ decimalsChoose a number form and keep its precision.Roots, powers & complex fractionsKeep every expression grouped correctly.Function notation that makes senseEvaluate, find inputs, and compose functions.Read the features that matterIntercepts, vertices, windows, and restrictions.

SAT problem patterns

A point pairs one input with one outputPlot, name, and interpret ordered pairs, including points defined by a function.An intersection must satisfy both equationsSolve equations and systems, count solutions carefully, and report the requested quantity.Solutions to an inequality fill a shaded region; a dashed boundary is excludedInterpret shaded inequalities, strict boundaries, and context restrictions without trusting the visible window alone.A slider can estimate an unknown constant, and algebra finds its exact valueReason about unknown constants, repeated roots, sliders, and equivalent expressions.Squaring or canceling can create false solutions, so check the original equationFind absolute-value, radical, and rational solutions while checking signs and excluded inputs.A percent change is a multiplier: 15% off means multiplying by 0.85Calculate percent changes, reverse percentages, ratios, and unit conversions.An exponential model's exponent counts the growth or decay periodsInterpret growth factors, decay rates, starting values, and changes of time unit.Each repeated data value counts separately in a mean or medianUse lists for center and spread, distinguish frequencies from values, and reason about transformations.A circle's equation shows its center with flipped signs and its radius squaredRead circle equations, calculate coordinate geometry, and avoid conclusions based on a distorted graph.A number like 30 names a different angle in degree mode than in radian modeCheck degrees or radians, use right-triangle ratios, and interpret inverse trig outputs.

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Desmos practice

Evaluate a function

What does the question
need you to find?

Name the unknown.

Make the relationship visible.

Bring the result back to the question.

Some questions ask what a number means

What Desmos draws

Read the equation instead

A guide for the next question.

Calculator skills

SAT problem patterns

Desmos practice

Evaluate a function

What does the question
need you to find?

Name the unknown.

Make the relationship visible.

Bring the result back to the question.

Some questions ask what a number means

What Desmos draws

Read the equation instead

A guide for the next question.

Calculator skills

SAT problem patterns

Evaluate a function

What does the question need you to find?

Name the unknown.

Make the relationship visible.

Bring the result back to the question.

Some questions ask what a number means

What Desmos draws

Read the equation instead

A guide for the next question.

Calculator skills

SAT problem patterns

Evaluate a function

What does the question need you to find?

Name the unknown.

Make the relationship visible.

Bring the result back to the question.

Some questions ask what a number means

What Desmos draws

Read the equation instead

A guide for the next question.

Calculator skills

SAT problem patterns

What does the question
need you to find?

What does the question
need you to find?