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3 years ago

(3a+2.5b)^2=9a^2+6.25b^2+* Please help before Thursday

Mathematics

1 answer:

Anon25 [30]3 years ago

5 0

Step-by-step explanation:

We have (x + y)² = (x + y)(x + y) = x² + 2xy + y².

Let x be 3a and y be 2.5b.

Therefore (3a + 2.5b)²

= (3a)² + 2(3a)(2.5b) + (2.5b)²

= 9a² + 15ab + 6.25b².

Hence the '*' sign should be replaced with 15ab.

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Step-by-step explanation:

Given equations:

y = x² + 3x - 29 ------ (i)

y = 2x - 9 ---------------- (ii)

Now to solve this problem, we must determine the value of x and y;

Equate equations 1 and 2;

x² + 3x - 29 = 2x - 9

x² + 3x - 2x - 29 + 9 = 0

x² + x - 20 = 0

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So; solve for y now;

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