Đại số — SAT Math Guide

Chủ đề con

Linear equations in one variable

Solving equations of the form ax + b = c, including equations with fractions and variables on both sides.

Linear equations in two variables

Slope, intercepts, slope-intercept form, point-slope form, standard form, and contextual interpretation.

Systems of two linear equations

Substitution and elimination methods. Recognizing no-solution and infinite-solution cases.

Linear inequalities

Solving and graphing inequalities in one and two variables. Systems of linear inequalities.

Interpreting linear functions

Reading slope and intercept from context, identifying linear vs. non-linear models from tables and graphs.

y = mx + b (slope-intercept form)

y − y₁ = m(x − x₁) (point-slope form)

m = (y₂ − y₁) / (x₂ − x₁) (slope)

Ax + By = C (standard form)

New = Original × (1 ± r) (percent change)

Always check: does the question want the value of x or an expression like 2x + 1?
When given a word problem, define your variable before writing the equation.
For systems, elimination is often faster than substitution when coefficients align.
On the SAT, "no solution" means parallel lines; "infinite solutions" means the same line.