Answer: [1, infinity)
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Explanation:
Let's isolate x in the first inequality mentioned.
x + 7 ≥ 4
x + 7-7 ≥ 4-7
x ≥ -3
I subtracted 7 from both sides to undo the +7.
Now isolate x in the second inequality. We first add 8 to both sides, then divide both sides by 11.
11x - 8 ≥ 3
11x - 8+8 ≥ 3+8
11x ≥ 11
11x/11 ≥ 11/11
x ≥ 1
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The two solutions we found were
x ≥ -3 and x ≥ 1
Next, draw out a number line with closed circles at -3 and 1. Shade to the right of each closed circle endpoint as you see below.
Notice that the two inequalities overlap for x ≥ 1
In other words, if a number is -3 or larger AND 1 or larger, then the number is 1 or larger.
The two solutions intersect to form x ≥ 1
The inequality x ≥ 1 is the same as 1 ≤ x which is the same as 1 ≤ x < infinity
Then that turns into the interval notation of [1, infinity)
The square bracket includes the endpoint 1.
If needed, use the infinity symbol in place of the word "infinity".
