Evaluate the expression. [(12 x 5) - 10] : 5
1 answer:
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You can square the whole problem to cancel out the square root. Might make things easier.
Answer:
see explanation
see explanationStep-by-step explanation:
21
Note that
(a - )²
= a² - 2 +
= a² + - 2
= 11 - 2
= 9
Thus
(a - )² = 9 ( take the square root of both sides )
a - = 3
22
Since the expression is a perfect square, then
(4x + 5y)²
= 16x² + 40xy + 25y²
Comparing coefficients, then
a - 1 = 40 ( add 1 to both sides )
a = 41
23
99² - 87² ← is a difference of squares and factors as
= (99 - 87)(99 + 87)
= 12 × 186 = 1152, thus
24a = 1152 ( divide both sides by 24 )
a = 48