11.2 Straight-line graphs · Unit 11 Graphs

1 · Teaching slidesuse ← → keys

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2 · Key words

gradientHow steep a line is; the number in front of x.

y-interceptWhere the line crosses the y-axis; the constant.

straight-line graphThe graph of a rule of the form y = mx + c.

table of valuesA table of x values and the y values they give.

plotMark the points on the grid, then join them.

parallelTwo lines with the same gradient; they never meet.

3 · Summary of the sectionrevise from this

A straight line has the rule y = mx + c.
m is the gradient: how much y changes for every 1 that x increases.
c is the y-intercept: where the line crosses the y-axis, found by putting x = 0.
To plot a line: make a small table of values, plot the points, then join them with a ruler.
Two points fix a line, but always plot a third as a check.
A negative gradient means the line goes down from left to right.
y = 4 is horizontal; x = −2 is vertical. Neither is of the form y = mx + c.
Lines with the same gradient are parallel and never meet.

PDFPrintable worksheet All 58 questions, space to work PDFWorked answers Full solutions, not just the answer

Video lessons2 videos

Drawing graphs using an xy table

British corbettmaths

The safe method: table of values first, then plot, then join with a ruler.

Drawing Linear Graphs — worked answers

British stretchcorbettmaths

Full solutions to a practice set. Draw them yourself first.

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Straight-line graphs